Friday, November 28, 2008

What to oil - Part 3
Finishing the spring guns

by B.B. Pelletier

Part 1
Part 2

Today we'll finish with spring guns. In Part 2, we learned how to oil the piston seal and breach seal on a springer; now it's time to discuss all the other stuff.

What else is there?
How a gun is designed determines where it needs to be lubricated. A breakbarrel, for example, has fewer places to lube than a sidelever or underlever. But if you think in terms of friction, you should be able to figure out the lube points on any new gun, whether it comes with a manual or not.

Cocking mechanisms
The cocking effort must be transmitted through some kind of mechanism. In the Gat-type guns that have push-barrel cocking (The Crosman M1 Carbine, for example), the mechanism is greatly simplified, and the need for lubrication is reduced. Still, they have surfaces in contact with one another as the barrel slides back to cock the gun. Those need some kind of lube. Oil is probably better than grease because Gat guns have a long run of close tolerances, and you don't want the lube to gum up the action.


The Crosman M1 Carbine is a BB gun that cocks like a Gat.


A breakbarrel, in contrast, has only the pivot bolt, the sides of the breech or base block and the parts of the cocking link that need lube. For them, the load factor is higher, and a tough grease that won't break down or run off when hot is the way to go. I use Beeman's M2M moly grease for this part of the gun, and so do a lot of tuners. The moly particles bond with the metal surfaces they come in contact with, and they provide lube long after the grease is gone.


See the thin thrust washer that fits between the baseblock and the mainspring forks on both side of the gun? It's been greased with moly, which is proper for a tuneup. The pivot bolt also gets a coat of moly grease.



When the sliding cocking link is installed, it keeps the piston from rotating. It's also lubed with moly.


For underlevers and sidelevers, a lever takes the place of the barrel and the need for lube remains the same. Find the spots where the pivot points are located and lubricate every surface that touches.

I've seen just the basic lube job I described above reduce the cocking effort by several pounds. Of course, the gun that did respond so well was in dire need of lubricant. Most guns won't be in that shape, and a lube job will not have as dramatic an effect.

Mainsprings
Here I have to burst some bubbles, as there has been a great disservice done to airgunners for the past 40 years. I'm speaking about oiling the mainspring of a gun. The disservice is the fact that oil isn't normally the right lube to use on a mainspring. It is, however, the easiest lube to apply, which is why I think it has been pushed so hard. On many spring guns, there's a cocking slot through which at least part of the mainspring can be see once the gun is out of the stock, so airgun dealers have told shooters they should apply oil through that slot.

But oiling isn't enough for most mainsprings. They need grease, and the only way to do the job right is to disassemble the action and apply the grease directly to the spring. Sorry, folks, but that's a fact. This is especially true for the modern magnum springers. Oiling just doesn't get it, but it's easy and shooters feels they've done their part when they do it.


This is the correct amount of black tar for a mainspring for a rifle that vibrates a lot. For one that has a spring that's sized closer, you only need a fraction of this amount.


With guns that shoot under 12 foot-pounds and have leather piston seals, I like to see a medium-weight grease used--something lithium-based, perhaps. For all others, I like the more viscous greases that don't fling off--the black tars, if you will. How much you use depends on what you're trying to accomplish. You may remember that I recently tuned an HW55 with just a kiss of black tar. It sped up the gun without bringing any vibration into the operation. That's about as perfect as you can hope for.

Triggers
Nothing responds to a lube job as much as a cheap trigger. And an expensive one barely changes at all, if you even notice it. There are triggers that become unsafe with lubrication. Those found on BSF rifles and pistols come to mind. I lube my triggers with Beeman M2M moly grease. Dr. Beeman once wrote that moly was too slippery for triggers, but I found that only the unsafe triggers had a problem. You shouldn't lubricate them at all.


I lube only good triggers, such as this Rekord, at the sear contact. Enough oil gets on the other parts, like the bearings, through general handling.


Well, that's it for lubricating airguns. I've covered CO2 guns, pneumatics and now spring guns. Remember that it's usually best to lube less than more, with the exception of Pellgunoil on pump piston heads and CO2 cartridges. There, it's impossible for a reasonable person to use too much oil.

Thursday, November 27, 2008

The AirForce match sight set - Part 2

by B.B. Pelletier

Happy Thanksgiving!

Part 1

In the first report, I told you this sight set is the Edge sight set, but that was incorrect. The front sight in this set is not the same sight that's on the Edge rifle, though the two look similar at first glance. How they differ is the subject of today's report.

The photograph on the Pyramyd Air web page is one of the actual front sight used on the Edge. What I'm showing you here is a pre-production prototype that will become the front sight of the set when it's released by AirForce in a week or two. After today's blog, you'll understand why the difference is important.

I also tricked you when I showed you the photo of the front sight in the first report. It was turned backwards, so you couldn't see what makes it special.


New AirForce target front sight is shown backwards in this photo. Adjustability is hidden.


Here are three pictures that are worth a thousand words.


Globe is elevated as high as it will go.



Sight elevation leg is adjusted as low as it will go in this configuration. That puts the globe at a medium height.



Sight elevation leg is on the opposite side and the plate that holds the globe has been turned sideways. Globe is now as low as it will go.


Adjustability
These three pictures portray the broad range of adjustability found in this front sight. You'll notice that not only can the globe be raised and lowered on the long post at the side, the plate that carries the globe also has grooves that allow it to be positioned high and low on the plate. Plus, the plate can be turned sideways for more mounting options. And, as I show in the last picture, the plate can be swapped to the other side of the sight, where all the elevation possibilities are also available.

For all these globe locations, the aperture will remain centered over the barrel. You can adjust the globe up or down to fit any gun you put it on. Don't be fooled by the offset split in the sight base--the center of the globe is directly above the center of the 11mm base.

The transparent aperture is a proprietary AirForce size. They will offer different apertures, as well as a set of graduated sizes as an option.

What does it fit?
To use this sight, your rifle must have dovetails set 11mm apart. Just because there are dovetails on the muzzle of your gun, don't assume they're 11mm apart, because many are not--especially on sporting rifles. The dedicated target rifles, however, often do have 11mm front sight bases, but always check before you buy.

What about the Edge?
I told you that this sight is not the one that comes on the new Edge target rifle. The reason is the Edge is always set up the same way, so its front sight doesn't need to adjust up and down. This sight is made for rifles other than the Edge, where the correct sight height will have to be established.

In the next report, I'll look at the rear aperture sight.

Wednesday, November 26, 2008

Walther Talon Magnum - Part 3

by B.B. Pelletier

Part 1
Part 2



Today I'll look at the accuracy for the Walther Talon Magnum. You'll remember that this rifle is the .177 caliber version of the Walther Falcon Hunter, which comes in .22 and .25 caliber.

The first step was to mount the scope that comes with the rifle. It's a 3-9x32 that has no parallax adjustment, so whenever you shoot closer than about 25 yards you dial the magnification down until the image becomes clear. The scope comes already inserted in one-inch rings, so all you have to do is mount the rings on the base that's on the spring tube of the rifle.


The scope rings are already installed on the scope. The bases have no scope stop, but you can use the stop on the rifle base.



The rifle base is a strangely notched 11mm dovetail. It would seem that these notches have a purpose, but they don't work with any scope mounts we know of. The scope stop plate is a plain plate screwed into the top rear of the base.


The scope mounted with the reticle aligned correctly and the rings attached with slotted thumbscrews, so the job was quickly finished. Use a coin to tighten the thumbscrews.

Holding technique
I knew from testing the Walther Falcon Hunter that this rifle doesn't respond to the artillery hold. This one wants to be held firmly, like a deer rifle. My range was 21 yards and I began the test with Beeman Kodiak pellets. The rifle was on paper in three shots, and the scope adjusted fine. The optics were not as clear as I would like, but you can always upgrade the scope later.

Kodiaks settled into a 3/4" group. The rifle wants to be held firm into the shoulder and a firm grasp on the forearm, and then it will become very predictable. I also tried Crosman Premier 10.5-grain heavies, but they didn't group as tight as Kodiaks.


A typical group of Beeman Kodiaks looked like this at 21 yards.


As I shot, two things became clear. First, the trigger was getting smoother very fast. I could actually sense it becoming smoother as I shot, so it probably won't take but about 500 shots to break in all the way. The second observation is that the scope mount screws need constant attention. They loosen from the harsh vibration of each shot.

I tightened the stock screws just once and was surprised to find that the forearm screws have a LEFT-HAND TWIST! The triggerguard screws are right-hand.

RWS FTS pellets
I also tried RWS FTS pellets. They're an older domed pellet that weighs 10.5 grains. But they weren't even on the paper at 21 yards, and since the other pellets were, I didn't adjust the scope to get them on.

JSB 8.4-grain domed pellets may be best
I ended the test with JSB Exact 8.4-grain domed pellets. They grouped about the same as Kodiaks, on average, but one group was tantalizingly tight.


JSB Exact 8.4-grain pellets grouped about the same as Kodiaks at 21 yards.



This one group of JSBs was much tighter than the rest. I don't know what caused it, but with more testing this may prove to be the best pellet for this rifle.


The bottom line
Some of you have to shoot a .177 caliber rifle because of legal reasons. If that's the case, this one's a real bruiser. But if you can shoot a .22 or .25, I would go with the .22 caliber Walther Falcon Hunter. I say that because there are more good .22 caliber pellets available than there are .25s, and they're less expensive. And the .22 produces so much more energy than the .177 in a powerful spring rifle like this.

But if you're going to hunt with a .177 breakbarrel, this one offers a lot of value for a very low price.

Tuesday, November 25, 2008

Airgunner's Christmas Gift Guide - Part 2
Gifts under $50

by B.B. Pelletier

Part 1 - Under $25

Here's a link to Pyramyd Air's official Gift Guide.

Sorry to rush things, but tempus fugit. Today's post will include some airguns.

For those who are not familiar with these guns, here are a few pointers.

1. For target practice, the velocity can be very low--350 f.p.s. is all that's needed.

2. None of these airguns are recommended for hunting, but a few that get up to 750 f.p.s. have limited use in pest elimination.

3. BB guns such as the Red Ryder and the Crosman 760 shoot steel BBs that bounce back from hard targets. Be sure to get safety glasses for everyone who will be in the vicinity of the shooter. Get a good BB trap that will stop the BBs without letting them bounce back. Lead pellets do not bounce back, but they still require a good pellet trap for safe shooting.

4. In this price range, the CO2 guns will not last as long as more expensive CO2 guns. The most reliable guns are the spring-piston BB guns like the Red Ryder.

Air rifles and BB guns
Crosman 760
Pink 760--just a dollar more
Daisy Red Ryder
Pink Red Ryder--50 cents cheaper!
Daisy 880
Daisy 840

Air pistols and BB pistols
Beeman P17 pistol
Crosman 357 revolver
Crosman C11 pistol BB gun
Daisy Powerline 15XT BB gun
Daisy Powerline 693 BB gun
Tanfoglio BB pistol

Airsoft guns
Tactical 1911 CO2 pistol
Tactical M92 CO2 version
UHC 132 revolver 6-inch
Crosman Pulse P70
Walther P99 Special Operations
M14 Sniper Spring airsoft rifle combo
Crosman R71

Other stuff
Beeman swinging silhouettes
Gamo 50" padded rifle case Fits a longer scoped air rifle up to 49".
Plano rifle case, single scoped Fits a single scope rifle up to 52" long. Hard case.
Blue Book of Airguns 7th Edition Every airgunner needs this book.
Daisy pellet trap Perfect for low-velocity pellet guns that don't shoot faster than 650 f.p.s. Not for steel BBs.

Next week, I will do a guide for gifts of $100 and under and the last guide will be for gifts of all prices.

Monday, November 24, 2008

Big bore airgun hunt - Part 2

by B.B. Pelletier

Part 1

The Wildlife Ranch puts you up for a night, so there are no room rents but you're on your own for food. Fortunately, the town of Mason has several nice restaurants, as well as a small grocery store. We were in town during the height of deer season, which runs all November and December, and everywhere we went we ran into other hunting parties hunting on different ranches. The signs in every building in town told us that hunting is the principal industry in this central Texas community.


Texas Wildlife Ranch in Mason, Texas was the headquarters for our two hunts.



Inside the store, a wide variety of game animals are displayed. The full-body mount on the right is an aoudad ram--our first quarry.


The morning of the hunt dawned with the threat of a thunderstorm. By the time we arrived at the ranch to pick up our guide, it was 6:45 and the heavens finally opened, delaying our start for an hour. Not that we might melt in the rain, but a Texas thunderstorm is not weather in which you want to be walking outside. So, it was about 8 a.m. when we finally reached the hunting grounds.

Eric ran his gas-powered compressor to fill a pony bottle to 4500 psi, which gave him three refills of air for the hunt. We would be hunting several miles from the trucks, so this is like carrying extra cartridges for a firearm.


Henderson fills a pony bottle before setting out.


We initially stalked a herd of Sitka deer, but after more than an hour and a couple failed stalks, they ran into a huge open field where we lost all chance of getting close.

Going through the country, we came upon several places where coyotes had finished an animal and left the remains to be picked clean.


Coyotes hunt in packs to bring down the weak and the young. You see bone piles like this everywhere. I found a complete aoudad skull with horns in the rocks during the stalk.



Talk about Jurrasic Park!


Eric decided to finally go after the aoudad ram he's been wanting. Also known as the Barbary sheep, the aoudad is the most elusive animal at the Texas Wildlife Ranch. They live in the high rocks that offer them good visibility of any approach, and they spook easily. Getting to within airgun range or under 100 yards was going to be an ordeal.


The rocky terrain preferred by the aoudad will get your heart pumping after a few minutes!


Why a hundred yards, when I already told you Eric had bagged a goat two days before at 147 yards? Well, the aoudad is several times the size of the goats Eric bagged. They can weigh 225 to 300+ lbs. and are tough as nails. It takes not only great power to drop one but a perfect shot in the boiler room, which is the heart-lung area. Eric's Quackenbush .308 is simply not enough gun for this game. It can drop a whitetail deer, but not an aoudad.

So, he was hunting with a Quackenbush Outlaw .457 Long Action, a 550 foot-pound rifle. He scaled back to a light 300-grain bullet to get a flatter trajectory, but that was as far as he dared to go. And that combination gave him a 100-yard rifle. However, with some careful movement through the high rocks that are this sheep's natural habitat, he was able to get closer.

Three times he stalked the animal, and three times the game bolted before he could take the shot. Our team of four plus the guide probably walked two miles through the high rocks before a good shot was possible. But when it came down to business, one was all it took!


Henderson took this trophy aoudad buck with one .45-caliber bullet from his Quackenbush .457 Long Action.


We broke for lunch after Eric's successful hunt. A drive into Mason landed us at the local pit beef barbecue place for our maximum daily ration of cholesterol. Then, back to the ranch to meet Richard, our guide for the second hunt.

This time, Paul Capello was the hunter and Eric armed him with the Quackenbush .457 Destroyer. He chose .457 Hornady round balls because Paul's intended animal was a Merino sheep--a little smaller and less secretive than the aoudad.

When we unloaded in the hunt tract, we immediately saw small herds of different exotics roaming in the field. We were on a tract in which the animals would cost either $185 or $300, depending on the size and horn development. The Merino sheep is widely regarded as having the finest and softest wool in the world, as many sweaters and high-grade mattress pads can attest. They're pure white, though in the wild they get covered with dirt and look dingy gray.

We walked about a quarter-mile into the tract before spotting a pair of Merinos that looked interesting to Paul. It took two stalks in the 85-degree heat of the Texas sun before he got to a good spot, but all was not well with the sheep. The two males were standing side by side, and one shot would have taken them both, so Paul had to wait for them to separate. It took several minutes before the larger of the pair decided to walk off on his own, giving Paul a good shot at about 40 yards. Remember, he was shooting with open sights.


Not one but two sheep are standing side-by-side just left of center at 40 yards (enlarged for definition). We had to wait for them to separate.


His first shot was right through the boiler room, as we learned later, but the animal didn't fall. This is characteristic of hunting with a big bore and it's very similar to bow hunting. After waiting several seconds, the animal became wobbly, so Paul put a second ball through him within two inches of the first one. That knocked him over, and it was quiet shortly thereafter. Both balls completely penetrated the sheep and were lost, but a fragment of one was embedded behind a rib, where it had become lodged on its way out.


Paul's Merino was a good one, dropped with two good shots. The pelt will clean to pure white.


Eric's aoudad is a $3,500 trophy--highly sought-after by hunters around the world. Paul's Merino was $300. Prices at the Wildlife Ranch start at $185 for smaller animals and go up to $4,000 for a trophy bison. A whitetail deer trophy runs a flat $1,500. Compare that to paying a minimum of $2,500 a year for a deer lease, which brings additional expenses and no guarantee of success. Texas has almost no public land on which to hunt, so these are the best options for most hunters. Having lived in Washington state, Maryland, Kentucky and Ohio, where public hunting is free and plentiful, I know how absurd that sounds. After living in Texas for five years, I also know it's the truth.

For those of you who don't live in Texas, exotic game ranches are a huge boon, because you can fly in, hunt and fly back home. The trophy and any taxidermy can be shipped to you later, and the meat can be frozen for shipment, as well. Many hunters choose to let the meat be donated to one of several local food kitchens, so nothing goes to waste.

Remember, this was a blog about hunting game with a big bore airgun. No state has yet enacted legislation to allow big bore hunting, so this is one very viable option. When you buy that Career Dragon Slayer, you can start dreaming of your own big bore hunt.

Friday, November 21, 2008

HW 55 Tyrolean - Part 7
Time to test the tune

by B.B. Pelletier


Part 1
Part 2
Part 3
Part 4
Part 5
Part 6

Today, we'll put the HW55 back together (finally!) and see how well it performs. You'll recall that I cleaned, adjusted and lubricated the trigger in the last report. This will be the first time I've been able to examine the job with the rifle in the stock. That makes a huge difference in the feel.

Which mainspring?
You may also recall that I had a choice of mainsprings to try. In part 5 of the report, I talked about how to measure a mainspring before fitting it to the rifle. Well, I was surprised this time. The spring I chose was so close to the internal dimensions that, when it compressed, it became too large to fit and the rifle could not be cocked. The length was never an issue because I couldn't break the barrel far enough to cock it anyway. My initial plan was to remove coils to get the right length, but that didn't take the width of the compressed spring into account. On to plan B.

Plan B was to use a smaller spring that would certainly fit the rifle. And it did. In fact, it's a much better fit than I had hoped to get. It's only slightly smaller than the mainspring I took out of the rifle. I put just a kiss of black tar on the coils to dampen any vibration--so little that the spring now looks dirty rather than black. That's going to give the max power the spring can generate, so let's hope it has what it takes.

The spring guide is Delrin, a self-lubricating hard synthetic often called engineering plastic. That's a modern change from the steel guide the 55 came with; being self-lubricating, it offers maximum velocity without lubricants. It fits the spring very snugly, so all hint of vibration is gone from that part of the gun.

The new spring expands to take up the entire inner space inside the piston, so another vibration cause is gone. When the rifle fires, the spring goes back to its almost uncompressed diameter. That's where the hint of black tar should come in.

The piston seal got a coat of Beeman Metal-2-Metal moly paste. Some of that will burn off with the first hundred shots, but it will also burnish into the compression chamber walls where it'll provide lubrication for many years to come. The last tuner did the same thing, so this gun is probably lubricated for at least the next 10 years. No chamber oil is required. The piston seal fits the chamber very tightly, so compression should remain at its peak for all that time.

This tune will either work well or not, and the only way to tell is to button up the rifle and shoot it. So that's what I did. And the first shot was very satisfying. The gun is now a bona fide HW55! There's no vibration and the trigger breaks as crisp as a glass rod snapping.

I found that the locking lever had been adjusted as loose as possible, but the mechanism was very dry so I lubricated it. That reduced the required effort to unlock the barrel a little, but not as much as I would have preferred. The rifle is still too new and needs a few thousand shots to wear in. The breech seal is in perfect shape and is sealing the barrel exactly as intended.

Cocking is still light and smooth, though the barrel does have to be pressed all the way back for the trigger to catch the sear. On the closing motion, the dreadful "ratchet-y" drag of the cocking arm over the mainspring has been reduced about 80 percent. You can still detect it, but it's a world better than before.

The trigger is HW55-fabulous! I adjusted it to about 14 ozs. That's heavy for a pure target rifle, but good for use by non-target shooters. It still takes getting used to, but it isn't dangerous.

Velocity with Meisterkugelns
Before the tune, the rifle averaged 516 f.p.s. with RWS Meisterkugeln pellets. The extreme spread for 10 shots was 27 f.p.s. After the tune, it averages 546 f.p.s. with an extreme spread of 15 f.p.s. Slightly faster and considerably more uniform.

Velocity with RWS Hobbys
Before the tune, the Tyrolean averaged 598 f.p.s. with RWS Hobby pellets, and the extreme spread for 10 shots was 40 f.p.s. After the tune, it averages 631 f.p.s. with a spread of 15 f.p.s.

Velocity with blue-label target pellets
Before the tune, the rifle averaged 598 f.p.s. with the Chinese-made target pellets I use for air pistol competition The spread was 21 f.p.s. After the tune, it averages 633 f.p.s. with a spread of 19 f.p.s.

Bottom line
In summary, the tuneup turned out very well. The barrel lock still needs to be worked-in and there 's still some drag on the closing stroke, but this rifle has taken a new lease on life. I wouldn't think of opening it again for at least a decade and maybe longer if it holds up.

I'm going to use the rifle for one more test of the new AirForce aperture sight.

Thursday, November 20, 2008

Airgunner's Christmas Gift Guide
Gifts under $25

by B.B. Pelletier

Here's a link to Pyramyd Air's official Gift Guide.

A reader asked for this about a month ago, and it's time I got started. I'm breaking this into price points so gift-givers can choose their limits. The way this works is you send your relatives and friends to this page, and I point them to things I think airgunners might enjoy. Each item will be linked, but as we get closer to Christmas, Pyramyd Air will run out of many things, so have a fallback plan in place.


Santa leases back the Pyramyd Air Warehouse for special Christmas gifts.


Note to the gift-giver
The things in these Gift Guide blogs are my choices for airgunners. Please ask your favorite airgunner to point you in the right direction, so I don't steer you wrong. I'm doing this because I know how difficult it can be to find a gift for someone with a specialized interest like airguns.

Pellets
First, ask your airgunner what caliber or calibers of airguns they shoot. Pellets come in many calibers, but the most common smallbore calibers are .177, .20 (which is also called 5mm), .22 and .25. I will only name those pellets I feel are the very best for each caliber.

.177
JSB Exact Diabolo Heavy pellets (10.2 grains) My top pick.
JSB Exact Diabolo pellets (8.4 grains)
Beeman Kodiak Extra Heavy pellets (10.6 grains)
Crosman Premier Heavy pellets (10.5 grains)For pneumatics and CO2 guns
Crosman Premier pellets (7.9 grains) For spring guns.
RWS Hobby pellets (7 grains)

.20 caliber (also called 5mm)
Crosman Premier pellets (14.3 grains)
JSB Exact Diabolo pellets (13.5 grains)
Benjamin Cylindrical pellets (14.3 grains)
Beeman Field Target Specials pellets (11.45 grains)

.22
JSB Exact Jumbo pellets (15.8 grains) My top pick in this caliber.
JSB Exact Jumbo Express pellets (14.3 grains)
Crosman Premier pellets (14.3 grains) A close replacement for JSB pellets.
Beeman Kodiak Extra heavy pellets (20.1grains) Better in guns producing over 20 foot-pounds of energy.
RWS Hobby pellets (11.9 grains)

.25
Beeman Kodiak Extra Heavy pellets (30.7 grains) My one and only pick in this caliber.

Don't overlook Pyramyd Air's "Get the fourth tin free" offer. If you buy 4 tins or packages of smallbore pellets (the calibers above), they'll give you the least expensive package or tin in your order for free. That offer extends to multiples of 4 tins, so if you buy 8 tins, 2 will be free. You have to put the 4th tin in your shopping cart, and the money will be subtracted when the order is placed.

Airguns
There are a few BB guns available for less than $25:

Daisy Model 105 Buck BB repeater
Marksman 1010 BB, pellet, dart & bolt pistol

There are also some airsoft guns that I can recommend in this price category. Airsoft guns shoot 6mm plastic balls that the Asian manufacturers call BBs. They're not the steel BBs that American-made BB guns use. These plastic BBs are both larger in diameter and lighter in weight than steel BBs, so they don't have the same potential for injury if they strike a person. Nevertheless, Pyramyd Air does not recommend or condone shooting any gun at a person or animal, except in the specialized practice of hunting and pest elimination. Parents must be warned that airsoft guns can produce serious injuries and should not be given to young children to shoot without supervision.

The guns I'm selected are the best in their price class and will give decent service. Don't expect them to last like a higher-quality airgun.

Airsoft 904 by UHC Buy any brand of 0.12-gram BB for this gun (click on the "Ammo" link in the description). The same holds true for all the recommendations that follow.

Airsoft Spring Pistol UHC 92

Crosman Stinger Kit P30

Crosman Stinger P30

Tanfoglio Witness 1911 Pistol

I'm giving you a link to the airsoft spring pistol page because there are other models in this price category that might suit you better. At this price, you are going to be able to purchase only spring guns, which is where that link takes you.

There are a few long guns in this category, but I didn't recommend them. That doesn't mean they aren't good. I just don't have any experience with them.

Other things for under $25
This is my list of other items that are priced under $25. There are too many items for me to get them all, so this is just a smattering.

Crosman Airsoft Target For use with airsoft guns ONLY.

Crosman Auto-Reset Electric Airsoft Target For use with airsoft guns ONLY.

Cybergun Magic Sticky Target For use with airsoft guns ONLY.

Gamo Squirrel Field Target For shooters who want to try their hand at field target.

Airgun pellet auto-reset target

CO2 cartridges For shooters who need CO2 cartridges for their guns.

Crosman Pellgunoil The perfect stocking-stuffer. Most airgunners need this stuff and always forget to buy it.

American Air Rifles A great book for all airgunners.

Ballistol Another stocking-stuffer every airgunner needs.

Beeman M-2-M Moly Paste The slickest grease known. This stuff is messy, so get some Lava soap for the mud room to go with it.

Crosman clear adjustable safety glasses Every airgunner needs to wear a pair of these when shooting or when standing near shooters.

That's my list for under $25. In the near future, I'll also produce lists for under $50, under $100 and unlimited prices.


Large or small, your airgunner's gift can be found at Pyramyd Air.

Wednesday, November 19, 2008

Big bore airgun hunt - Part 1

by B.B. Pelletier

As you know, I went big bore airgun hunting last week. I didn't shoot anything myself, but I accompanied Eric Henderson to The Wildlife Ranch, located in the central Texas Hill Country. We sighted-in several different big bores and went on two exciting hunts. Many of you wrote that you are interested in this kind of hunting, so I want to explain it all to you.

Exotic game ranches
Texas is home to the largest concentration of exotic game ranches in the United States. On these ranches, game is stocked, bred, managed and turned loose on large hunting tracts where hunters can hunt them for a fee. This kind of hunting has been taking place for about 20 years and is rapidly growing in popularity because of the accessibility for hunters. The place we chose to hunt was The Wildlife Ranch in Mason, Texas.

Some of the animals on The Widlife Ranch are now extinct in their native lands as a result of poor game management regulations, so one important service the ranch provides is the repopulation of animals back into their native habitat. By a quirk of fate that the PETA folks will never admit, the exotic hunting programs in the United States have saved several species from extinction and are now responsible for the creation of a second chance for game in their original lands.

Another benefit of exotic game ranches is that they allow much broader hunting seasons. The game laws of a state do not extend to animals not native to that state, so the animals on the exotic game ranches are managed by the ranches. By another not-so-strange quirk of fate, these ranches have been able to create large herds of game while making it possible for hunters to hunt most of the year. Since they manage the nutrition and health of the animals, as well as providing "safe haven" tracts, where no hunting is possible, the ranches have created the perfect environment for growth. The result is a series of large ranches that offer hunting opportunities year-round for hunters who are willing to pay.

Let's talk airguns
I'll tell you much more about this later, but now I want to get to the airgun side of the hunt. Eric Henderson was hunting with a variety of Quackenbush rifles. He had taken two rams with his .308 the day before we arrived. One was taken at 112 yards and the second was at 147 yards. For those who think air rifles are for short-range only, here's your comparison.

Eric's larger-caliber Quackenbush .457 Long Action has a lower muzzle velocity that comes with a more pronounced trajectory. He shoots 300-grain .457 lead bullets that give energies in the mid-400 foot-pound region and are perfect for animals the size of a large mule deer.


Examining a Quackenbush .457 long-action with a special-order long barrel.


We confirmed Eric's zero with a couple shots the night before the hunt at the house where we stayed. The house was located on a ranch of several hundred acres, and safe shooting was possible in the side yard, located a few feet from where the trucks were parked.

Disaster strikes!
After the principal rifle was confirmed, I set up a scoped Sam Yang 909S for Paul Capello, who was to take the second hunt. The first two shots went well, but after the fill from my 12-year-old hand pump, the exhaust air blew a huge cloud of dust onto the pump shaft, killing it. There was no backup to fill the rifle because the Korean adaptor is non-standard, so Paul had to make other arrangements.

That pump has served me honorably for over 12 years, but now it needs an overhaul. And this is a sharp lesson in adapters and the need to have a backup plan.

As it turned out, Eric had a Quackenbush Destroyer--a one-of-a-kind .457 light rifle built with a dump valve. It gets but a single shot before refilling, with the tradeoff that it produces 950 f.p.s. and 287 foot-pounds with a .457 Hornady round ball from a 4-lb. gun! Eric has the rifle set up with a three-leaf folding express rear sight, so Capello was going to hunt the old-fashioned way!

I fired the Destroyer with a 300-grain bullet and noted that it had a very light trigger and quite a kick with that heavy bullet. With round balls that weigh less than half as much, the recoil is lighter.

Paul became accustomed to the rifle within several shots. There was no sight-in required because the express sights are fixed and never move.

The daylight faded as we finished our preparations for an early hunt the next morning. Paul, being a New York resident, had gotten a provisional Texas 5-day hunting license for $45, but there is no additional licensing requirement for hunting exotic game. We were set for the hunt!

Tuesday, November 18, 2008

Walther Talon Magnum - Part 2

by B.B. Pelletier

Part 1

Before we begin, don't miss the video of the 2008 Roanoke Airgun Expo.


Walther's Talon Magnum is the .177 version of the Falcon Hunter. This is a big air rifle!


Today is truth day for the Walther Talon Magnum. We're goiung to test velocity. This is the .177-caliber version of the Walther Falcon Hunter, which comes in either .22 or .25 caliber. The .177 promises a muzzle velocity of 1400 f.p.s. with super-light pellets and 1200 f.p.s. for lead pellets. Today, we'll find out how close it comes.

This is a BIG airgun!
I have to reiterate that this rifle is not for plinking. It's made for hunting. Period. The 50-lb. cocking effort will put a strain on those biceps, whether you're in shape or not. And the effort needed to break open the barrel is fully equal to the British-made Webley Patriot. Even closing it takes a forceful slam.

Trigger-pull
The trigger is two-stage and very long and creepy. It surprised me with a release weight of just 4 lbs., 14 oz. I was expecting the scale to top out at 8 lbs. before the rifle fired. I think a long break-in will help both the trigger and the cocking effort, though neither will ever become light.

Crosman Premier 10.5-grain pellets
I started the test with Crosman Premier heavy pellets to get the detonations out of the way. Indeed, the first several shots were much higher than the average velocity of 904 f.p.s. That gives a muzzle energy of 19.06 foot-pounds. The spread of this string was 892 f.p.s. to 914 f.p.s., which is pretty tight for a new gun.

RWS Clubs
RWS Club pellets were next. They weigh 7 grains even and are expected to go supersonic. They averaged 1132 f.p.s. in this rifle, with a spread from 1113 to 1148 f.p.s. The muzzle energy of the average velocity is 19.92 foot-pounds. As expected, the lighter pellets give greater energy in a spring-piston gun. The spread is on the high side, but not out of reason for a new gun.

RWS Superdomes
RWS Superdomes came next. These 8.3-grain pellets gave an average velocity of 1065 f.p.s. The spread was from, 1047 to 1085 f.p.s., which is a little larger than we like to see. Perhaps, when the oil burns off, the gun will stabilize. The average velocity gives an energy of 20.91 foot-pounds, which is really getting up there for a .177 springer.

BUT DON'TCHA WANNA KNOW HOW FAST IT GOES?

Of course you do! Many of you know better, but this is like the accident on the side of the highway--you just gotta peek.

Crosman Silver Eagle Hollowpoints
The Walther Talon Magnum is one of the fastest spring-piston air rifles ever produced. With Crosman Silver Eagle Hollowpoint pellets, it averaged 1,323 f.p.s. The spread was from 1156 f.p.s to 1,543 f.p.s., but a look at the entire string of ten shots will prove revealing:

1543
1253
1200
1534
1404
1156
1292
1329
1229
1293

I hope you can see that the average I computed is probably not representative of the gun. It's still detonating too much for the numbers to be correct. Or, perhaps better put, this is a case where a sample of 30 shots would be more exact than 10. Even then, the gun is adjusting itself; the average in another thousand shots will probably be lower. I would expect something in the low 1,200s when the gun is fully broken in.

This is a big, powerful air rifle. Buy it knowing that and you shouldn't be disappointed.

Monday, November 17, 2008

The Crosman 1400 Pumpmaster: an American classic--Part 2

by B.B. Pelletier

Part 1

My rifle gets the following ballistic performance with various numbers of pumps. I stop at eight strokes of the pump, because there IS a limit to what the valve can take--blow-off design notwithstanding! Over-pump a 1400, and you'll soon need a new valve, as the excessive pressure will extrude the seal material right out of its seat! More on that in a moment.

Velocity with 14.3-grain Crosman Premiers
Oiled with FP-10, point-blank, 60-deg. F


2 pumps...345 f.p.s.
3 pumps...415 f.p.s.
4 pumps...471 f.p.s.
5 pumps...514 f.p.s.
6 pumps...547 f.p.s.
7 pumps...573 f.p.s.
8 pumps...598 f.p.s.


The velocity figures for my 1400 seem low for the gun. I've had others that shot Premiers in the mid-600s, and I once owned a 140 that got 740 f.p.s. on 10 pumps. This rifle would never get near that velocity, as the diminishing gains clearly show.

Still, the rifle delivers 11.36 foot-pounds of energy with the very accurate Crosman Premier. That's enough to bag a rabbit at 20 yards or so. A gain of several foot-pounds could undoubtedly be realized (with a loss in velocity) if a substantially heavier pellet were used.

You can't pump forever!
One thing many of us overlook when we talk about this valve that can't be over-pumped is the fact that the valve material can be extruded by too much pressure. In other words, it is possible to ruin the valve by too much pumping, because the pressure will force the valve material through the valve seat. So there is a limit to the top end, even though it is impossible to make the valve lock up.

Fit & finish
The metal finish on my rifle is just mediocre. It's better than the finish on the typical Chinese airgun, but not quite up to the finish of current Spanish guns. Because of this, the blue is very uneven and there are patches where the bluing process was not completely stopped and corrosion set it. I find this to be typical of Crosman rifles from the mid-1960s to the end of the 1400 era in the 1980s. You can improve things somewhat with a soft abrasive metal polish (like Flitz), but there's a limit to what can be done. Be sure to oil the metal after polishing, or you'll promote new rust to replace the old.

The wood on 1400s varies greatly. Some rifles have a laminated wood stock called "Croswood," which looks quite striking. Others, like mine, have a muddy blonde finish over what looks like maple. This latter finish is brittle and chips off easily around the sharp contours of the stock.

The stocks varied in shapes and finishes over the years. The 1400 has had both a Monte Carlo stock with a strange swoop to the buttstock and a plain straight-comb butt. The Croswood laminate with the Monte Carlo is the most attractive of the bunch, although the raised cheekpiece is lowered so much by the downward swoop of the butt that there's no height advantage to either design.

To some collectors, the Crosman 140 and 1400 rifles represent the high water mark of airgun development. They like the steel and wood construction and the knowledge that they can't lock up their valves by over-pumping. This has kept the market demand for the guns somewhat higher than for equivalent older collectible Crosman rifles. An excellent 1400 often brings over $100, while a much older Crosman 101 in the same condition will only sell for $20-40 more. There's no rationale for this small a difference, other than acknowledging that the all-steel Crosmans have a following.

Friday, November 14, 2008

The AirForce match sight set - Part 1

by B.B. Pelletier

AirForce is very close to shipping their new match sights set, which consists of an aperture rear sight and a highly adaptable front globe sight. These items will also be available separately.

The sight dilemma
The airgunning community has long awaited a true precision target sight at an affordable price, and this one will be made right here in the U.S. The dilemma in target shooting is that you either have a plastic aperture sight that requires a special technique to use, or you have a sight that costs $350 or more. There hasn't been any middle ground for a long time.

Sporter-class sights have gear slack
Ten-meter target shooters who compete in the Sporter class are most affected by this lack of precision sights. Coaches around the country have learned how to deal with the Daisy/Crosman/Gamo/Air Arms/Chinese plastic aperture target sights, to coax as much precision from them as possible. But in the heat of a match, things can break down and shooters can forget that they have to move the sight three clicks in the opposite direction they want to adjust to take the slack out of the plastic gears--most of the time. Sometimes, the slack is out and they over-adjust. Their coaches have to watch them closely, or they'll lose a match because of an improperly adjusted rear sight.

The solution to this problem has varied over the years. Many years ago, the sights that came on the BS-4 rifle were available separately at a good price. They were rough but accurate copies of an older FWB sight, and they were more precise than Daisy's plastic aperture sights. Even when priced low, that sight didn't sell well enough for them to continue, so they stopped selling them altogether.

Gamo used to offer a pretty nice aperture sight that was made in Spain for the single-stroke target rifle they  sold. It was plenty good and the price was remarkably low at the time. Since Gamo also made that single-stroke rifle for Daisy, its rear sight became fairly well-known among the junior 10-meter shooters. Throughout the 1990s, it was the best cheap aperture sight around.

The original Daisy aperture sight that was available as an upgrade for the Daisy 853 rifle was pretty good for the price. But then Daisy started having it made in China, and the quality slipped. Then for a short time, Crosman had a reputation for having a better Daisy copy than Daisy had, because they were still getting the Spanish-made units. Then Gamo came on line with their own Daisy copy, however I don't see that one on the website. Maybe the Air Arms aperture sight has taken its place. They're pretty much the same sight regardless of the name.

Today, coaches know that to make adjustments, they first have to know how to take out the gear train slack of each individual aperture sight. If they follow the correct procedure, these sights can work very well, but there's a whole hodgepodge of different aperture sights out there, which makes it imperative for a shooter and coach to know each sight very well. Enter AirForce.

We've all been eagerly awaiting the new Edge target rifle that will dominate the NRA and CMP Sporter class when it becomes available. But a few years ago I learned that AirForce also planned to make their own aperture sights for the Edge--which is just as big a story as the rifle in my opinion. There's never been an American-made precision 10-meter aperture sight until now. Redfield made the famous Olympic aperture sight, but it was built for centerfire and rimfire competition and wasn't really a 10-meter design.

Front sight
The AirForce sight set is entirely new. It consists of a globe front sight with multiple mounting heights and configurations. It comes with a clear plastic aperture insert and additional inserts of varying sizes will be available soon. The new front sight can adapt to rear sight heights that vary over a broad range. I'll do a specific report on this sight and show several of the mounting possibilities.


New AirForce target front sight has numerous mounting possibilities. It can be mounted very high, very low or just about anywhere in between.


Rear sight
The new rear sight will be of particular interest to target shooters because it will sell for about $140--or less than half the cost of a similar European precision aperture. Where other Sporter-class aperture sights have click adjustments of 1/4 minute, this AirForce unit has 1/8 minute. Of course at 10 meters, the adjustments are only slightly more than a tenth as far as they are at 100 yards, but the AirForce sight really allows for adjustments of half the distance of the sights with which it competes.


New AirForce aperture rear sight adjusts high or low to suit the front sight. It will be sold separately for use with existing front sights.


Like the front sight, the rear has a large vertical range that can be adapted to most situations. When it's locked down, the adjustment knobs take over.

This new sight is for those who own a fine 10-meter rifle but have no aperture sight. Thousands were sold without sights to buyers who intended to scope them, but with this new sight they can now be reconfigured as real 10-meter target guns. Then there are other guns whose sights have been lost or separated by previous owners. You no longer need to spend another $400 to mount target sights on a rifle you buy.


Crisp click adjustments and vivid scales let the shooter know exactly where the sight is adjusted.


But the biggest customer will undoubtedly be those tens of thousands of Daisy 853 and 753 owners who want to upgrade their apertures and still be legal. They couldn't use the European sights on their guns, but the AirForce sight will be a sanctioned item of equipment for the Sporter class. I see the initial sales going mostly to these shooters.

I plan to test the rear aperture for this blog. The sights are expected to start shipping by the end of November or soon thereafter, and by then you should have a full report to help make your decision. No doubt you'll have many questions. Start asking them now, and I'll incorporate the answers into future reports.

Thursday, November 13, 2008

Hand pumps of antiquity - Part 3

by B.B. Pelletier

Part 1
Part 2

I returned from the hunting trip yesterday afternoon. I looked at all the back questions and then answered just a few. The rest I didn't answer, so ask them again if you really want an answer.

The hunt was very successful. I will tell you all about it next week, but tomorrow's post will be that new item I promised. Now on to today's report.

How pressure relates to velocity
The bottom line of this research is to provide some insight into how powerful the antique big bore airguns are by knowing what kind of air pressure they work with. There's no formula to calculate such a relationship, and it may be such a complex relationship that there never can be; there's a fair amount of information gathered from observation. For starters, let's look at Quackenbush's Brigand. On CO2, we get velocities around 575 f.p.s. with a .375 caliber lead ball weighing 83 grains. CO2 is nominally 900 psi. With the same rifle running on air at 1,200 psi, the velocity increases to somewhere between 730 and 775 f.p.s. Pressurize the gun to 1,500 psi, and the velocity drops to around 600 f.p.s., until the high pressure is lowered to the optimum range. Then it picks back up.

What we can say about the CO2 Brigand is that it has a valve that functions best with air pressured to between 1,000 psi and 1,200 psi--and it will function with limited results between 600 psi and 1,700 psi. That's a broad range of pressure but a much narrower band of optimum performance.

Looking at the outside lock rifle built by Gary Barnes, a rifle I haven't yet reported on, but will in the near future, we see an optimum range of performance from about 500 psi to 650 psi, with a working range of 300 to 800 psi. Oddly, although the outside lock functions at about half the pressure of the Brigand, it gets a few more shots on each charge of air. What's involved is a combination of caliber, barrel length and weight of the projectile.

To achieve high efficiency with low air pressure, the valve needs to remain open longer to allow air to continue to push the projectile until it's free of the muzzle. A large caliber provides more volume to lower the air pressure after it leaves the reservoir. The farther down the barrel the projectile gets, the more volume there is behind it, and big bores increase in volume faster than small bores.

To push a heavy projectile fast, you have to maintain the force pushing on it for as long as possible. That means a longer bore. A longer bore will diminish the air pressure behind the projectile very rapidly, unless the force is applied continuously.

What this means is that big bore airguns must leave their valves open much longer than small bore guns; to do that, they have to run on lower pressure. Note that when Quackenbush went from 1,200 psi to 3,000 psi, his velocity increased by only 118 f.p.s. (775 vs. 893). To get even that increase, he had to redesign the valve, because the standard valve wouldn't have functioned at the higher pressure.

What can we learn from this? Well, when we see a vintage .36 caliber air rifle shooting a round ball at 675 f.p.s., we now know it's about where it should be. Perhaps it might get up to 750 f.p.s. But a claim of 1,000 f.p.s. for a .65 caliber rifle with a 48" barrel should be met with some skepticism because of what it would take to actually achieve such performance.

I hope you were not waiting for some magical air pressure/energy calculator. I don't have one and I would doubt seriously anyone who said they did. A single gun and valve can be modeled fairly close, but once the design starts changing, all bets are off.

This process could be modeled, no doubt, but it would take more work than most people might imagine. There are variables that don't even become apparent until you start trying to estimate performance of a real design. So be wary of the person who tells you this is a simple linear relationship, because it is anything but.

Summary
The way antique big bore airguns are designed, there's no reason to over-pressurize them. They work well only within the narrow band of pressure for which they were designed and (sometimes) tuned. So, by knowing the specifications of the pump used to charge them, we can know what their operating range is, and that, in turn, reveals their performance in a general way.

My thanks to Dennis Quackenbush for providing the test data and the test pumps used in this article.

Wednesday, November 12, 2008

Hand pumps of antiquity - Part 2

This is the last day of B.B.'s hunt, so he'll start answering questions again on Thursday. Thanks for your patience.

by B.B. Pelletier

Part 1


The test fixture Quackenbush made to ascertain pump efficiency. The pump attached in this photo is the smaller one with the 5/8" piston head.


Empirical testing
I asked Dennis Quackenbush to tell me how much pressure a common hand pump can generate. He's been making replica pumps for vintage big bore guns for several years. Dennis' pumps are true to the old designs, except that they use synthetic pump seals. The old pumps had either a simple iron or steel piston that was lapped into the bore of the pump tube, or they used stacked leather washers on the end of the piston rod instead of a metal piston. The stacked washers were compressed by means of a nut so the fit could be controlled.

I've encountered several dozen antique pumps, and all of them were the type having the simple lapped iron piston. I only know about the stacked washer type from reading Air Guns by Eldon Wolff. He admits that the leather washer type is much rarer than the plain piston type.

Before Dennis conducted the tests, it seemed to both of us that neither vintage pump design could be the equal of one with a modern synthetic seal; so whatever pressure he could generate with a modern replica would represent a maximum for any vintage pump of the same physical specifications. That turned out to be an incorrect assumption, as we shall see.

We both agreed that the practical maximum force that could be applied would be the weight of the person doing the pumping. These early pumps had no mechanical advantage beyond that which is inherent in a single-stage mechanism. Although it would be possible to generate more force than one's weight by pulling the base of the pump toward oneself or by jumping on the pump handle, it isn't practical to do so--and it would be very hard to do it on a continuing basis.

Mechanical advantage is possible, and there are some vintage pumps that use it, but they're rare compared to the bulk of the pumps we know about. The single-stage manual pump is the most common design encountered in vintage airgun equipment.

Dennis saw where I wanted to go with this experiment, and he took up the challenge enthusiastically. He used two different vintage-type pumps of his manufacture, plus the modern Axsor pump to check efficiency. He provided the following data.


I pumped Quackenbush's test fixture to 500 psi and left it there for four months without air loss. Then, it was pumped up to 840 psi. Because I weigh more than Quackenbush, the higher pressure was easy to obtain.


Test of air pump efficiency
Quackenbush connected the pumps to a nine-cubic-inch test reservoir, to which he had attached a pressure gauge. He then pumped up the reservoir with each pump and counted the strokes required to get to certain pressure levels. He repeated this experiment three times to verify his figures, which is in the box below. Naturally, when you consider the number of pump strokes required to build pressure in the 5/8" diameter piston pump, he's not going to repeat each test 30 times! But, in the repetitions he did, the results were close enough to make the figures believable. If anyone doubts the data, they can buy a pump from Dennis and repeat the experiment themselves.




Next, he made another 5/8" diameter pump without a seal to test the effectiveness of something truly vintage. I felt sure he would not be able to reach the same pressure as a pump with a synthetic seal. This one had only a tightly fitted piston with a thin film of oil to seal it. The results were quite surprising! The pump with no seal went all the way up to the same pressure as the pump with the synthetic seal. Proving, once again, that we aren't as smart as we think.

Actually, it's incorrect for me to say this pump has no seal, for the oil film seals quite well. Dennis achieved 720 psi with the plain piston pump, using approximately the same number of strokes as the other 5/8" diameter pump that had the seal.

Then, on a suggestion from one of his airgunning friends, he tried "rapping" the air into the reservoir--similar to the method used with the Korean-built Yewah Triple B Dynamite shotgun. Rapping means imparting extra momentum to the pump through inertia. With this method, Dennis raised the pressure ceiling of the 5/8" plain piston pump to about 810 psi, but at a high cost to his personal well-being. He said his wrists hurt so much from doing the rapping just once that he had to recuperate for several days thereafter. So, rapping, while possible, is not a practical way to fill vintage reservoirs to higher pressures, and it's doubtful that anyone ever did it more than once.

One additional thing he did benefits this study even more than these test results. He noticed that the piston diameter relates directly to the total pressure achieved. By itself, this isn't such a great discovery because Cardew already published similar data in The Airgun from Trigger to Target. What Quackenbush did for us was remove the complex mathematical formulae from Cardew's work and substitute simple equations in their place.

Cardew says that 1,000 psi might be achieved by a heavy man. Quackenbush demonstrates that the pump stops at a point very close to the weight of the person doing the work...when the formula is applied.

Quackenbush’s proof
What the data show is that it's possible to calculate the maximum pressure for any single-stage air pump by simply dividing the weight of the pump operator by the area of the piston head. There should be some loss of efficiency due to friction in the pump, but this is most probably offset by some imprecision in determining the person’s body weight:

220 lbs. divided by .3068 = 717.08 psi


This allows us to build a "theoretical pump" that can generate whatever pressure we desire within the limits of physical laws. For example:

250-lb. operator using a pump with a 1/2" piston
250 lbs. divided by .19635 = 1,273.24 psi

150-lb. operator using a pump with a 1/2" piston
150 lbs. divided by .19635 = 763.94 psi


Notice that the stroke of the piston does not enter into this calculation. That's because the length of the stroke determines only how much air is being compressed. It doesn't affect the highest pressure that can be achieved. A longer stroke will compress a greater volume of air; a small-diameter piston will allow it to build to higher pressure.

Up to this point, the term single-stage has been used when referring to the pumps of old. Single-stage simply means that the pump is compressing air in one direction rather than on both strokes. In all cases, the direction for compression of a single-stage pump is the down stroke. The upward stroke sucks in more air for the next downward compression stroke.

The modern high-pressure air pump from Sweden, in contrast, compresses air in both directions. It's really two pumps nestled one inside the other, both housed inside an outer tube. [No, it's actually THREE pumps, nestled inside one another. And there is a new Swedish pump that claims to be four pumps!] Both pistons have a small piston diameter. The center of the larger pump is occupied by the smaller pump, so the AREA of the two piston heads is comparably small. The larger of the two is the second stage, which operates on the downward stroke--the direction in which the greatest force can be applied. The upward stroke sucks the air into the pump and pressurizes it slightly to begin with, thus making it ready for the second stage to compress it to a very high pressure level. This pump pressurizes a greater volume of air to a higher pressure than its small piston would normally allow because it acts as though it's twice as long as it is.

If a single-stage pump were made with a very small piston--perhaps 3/8", what sort of pressure might be possible from a 150-lb. operator?

150 lbs divided by .110446 = 1,358.13 psi


Of course, this small piston pump would take a lot longer to fill a reservoir, so we might increase its stroke to help matters. That gives us a long, thin pump that would eventually become too long to carry conveniently. Also, the thinner the pump piston, the thinner the piston rod; although the piston HEAD might be able to compress very high pressures, the rod that connects it to a source of force will eventually become too thin to bear up under the strain.

From this discussion, we see that Cardew was correct. It's possible to generate 1,000 psi and even more with a simple single-stage air pump.

Not only do vintage pumps begin to max out at pressures much lower than modern pumps can achieve, the guns being pressurized cannot deal with air pressures anywhere near these high levels.

The large valve contact surfaces of vintage big bores constrain them to use lower-pressure air. With the state-of-the-art technology available to 17th century airgun makers, it was all they could do to seal valves against pressures ranging from 400 psi up to 650 psi. They used horn and leather to accomplish as much as they did. Today's use of hard synthetic valve heads bearing on thin areas of contact on precisely machined steel seats was simply beyond anything they could achieve.

Also, they lacked the homogenous materials from which to make reservoirs to contain the higher air pressures. Even if they'd been able to make the valves and pumps to work at higher pressures, the reservoirs would have held them back.

Again, I turn to the documented studies that have been done to support this statement. This time, there's even less information than before. The number of ancient airguns that have been intentionally tested to destruction is almost zero. A fair number of them have blown up from too much pressure, but that was accidental; and apart from a big boom and possible injury to the operator, there isn’t much to go on. Cardew does mention one of the folded and brazed butt reservoirs that was tested to destruction.

Amazingly, the antique folded-iron reservoir held until 6,000 psi was developed. When it finally did blow, only one rivet popped, resulting in a controlled exhaust rather than a catastrophic explosion.

When such tests are conducted, the vessel being tested is never filled with air for fear of an explosion. Instead, oil or water is forced in under pressure, so the failure can only result in a safe leak. Unfortunately, this test is exactly the kind of report that a careless person will cite when trying to operate vintage equipment in an unsafe manner.

A case in point
Modern aluminum paintball tanks are designed to contain CO2 safely. CO2 has a pressure determined by temperature. At 70-degrees F, it's just under 900 psi. When the temperature rises to 95 degrees, the pressure increases to around 1,100 psi. Because of this variability, and because of the possibility of even higher temperatures, such as when a tank is stored in a car on a warm day (130 degrees is easily possible), the manufacturers rate the tank up to 1,800 psi. That's the number they put on the label on the tank for everyone to see.

Now, along comes Mr. Airgunner, and he reads this number. Okay, he thinks to himself, if this tank is rated to 1,800 psi, it's safe to pressurize it to that level. He fills it with air instead of CO2. The air tanks rated this high cost much more than the CO2 tanks (wonder why?), so using a paintball tank represents a real savings. If he does this, the tank is filled right up to its design maximu--a level that was engineered by the manufacturer to handle an emergency only. Because CO2 pressure varies with temperature, they make the tank to withstand a higher pressure in case the temperature ever rises unexpectedly. It isn't expected to withstand that pressure all the time, even though it's engineered to do so. It's expected to hold a pressure of around 900 psi when confined. Some folks go by the numbers without appreciating that they're actually subjecting these bottles to a 100 percent overfill. It doesn't end there.

If one person is willing to do that, what's to stop another from pressurizing the same tank right on up to 3,000 psi with the same fill equipment? Maybe he's been using paintball tanks this way for a long time, and there's never been any trouble before. "After all," he says, "these things are over-engineered, anyway."

Yes, they are. And, at 3,000 psi, you're more than 2/3 of the way into that safety margin. Standard pressure vessels are engineered to not fail with less than four times their standard working pressure--which you’ll remember is 900 psi, nominally. Blowup can occur any time after 3,600 psi for a tank having a 900 psi standard working pressure. That's for a new tank. Who's to say at what point an old abused tank will let go?

But tanks have safety valves (burst disks), don’t they? Again, yes, they do. Do you want to trust your life to a small piece of metal that's been sitting in the tank for years? What if the kid at the plant decided to use heavier sheet metal when your tank was made? What if there was a goof when the company placed the order and a stronger material was used without anyone's knowledge? What if someone in the field "fixed" it before you got it (perhaps to keep it from rupturing so easily)?

If modern paintball tanks represent a danger from over pressurization, what about vintage air reservoirs? They don't have burst disks or any other safety devices, plus they've been lying around for decades and centuries with their dubious metal walls containing who knows what kinds of pressure.

Also, the old reservoirs intentionally had grease smeared on the walls near the valve to catch and retain dirt and dust. At 500 psi, nothing is going to happen; but when you get one of these oldies up to 2,000 psi and more, that grease is going to vaporize into a highly explosive gas. Just ask a dive shop what happens when petroleum-based lubricants are used in scuba tanks. Boom!

When we work with precharged airguns of any type, we want to obey all the safety rules that pertain to them. When the airguns are also large bore, we want to be especially careful because they're so powerful.

Part 3 will demonstrate how pressure relates to velocity.

Tuesday, November 11, 2008

The Crosman 1400 Pumpmaster: an American classic--Part 1

Just a reminder that B.B.'s still on his hunt and may not be available to answer questions til Thursday. A lot depends on internet connectivity at the hunt site. Thanks to the many blog regulars who've been pinch-hitting for B.B.

by B.B. Pelletier


The 1400 is a small, sleek pneumatic rifle that really packs a punch


If you're a fan of multi-pump pneumatic rifles, you probably know about the Crosman 1400 Pumpmaster. If not, come along and take a look at this fine American classic air rifle from Crosman’s golden age.

The 1400 was the last in a series of rifles that began with the 120 model in the mid-1950s. The 120 was the outgrowth of the even earlier Town & Country Junior rifles, which were a replacement for the original Town & Country guns developed at the start of that decade. But that's as far back as it goes, for the pump rifles immediately before that were the 100-series that dated back to 1924 and the start of the Crosman Company's involvement in airguns. Those models have very little in common with these later guns.

The 120 was a non-descript underlever pump that gained some small fame when W.H.B. Smith reported on an experiment in which a pressure gauge was brazed into a 120 to ascertain how high the pressure would rise when the rifle was pumped. The experiment was inconclusive, though, when it was realized that the addition of the gauge increased the storage capacity so much that the pressure was affected grossly by the extra volume.

Other than that, the 120 was never a very successful or even exciting model for Crosman. It was replaced by the newer model 140, which had an exciting new blow-off valve, which ended the possibility of pressure-locked valves. Until that time, a pneumatic that was over-pumped could not be fired, as their internal pressure held the valve stem closed against the strike of the hammer. Owners either had to wait until the internal pressure leaked off and the gun could be fired (which could take weeks), or they had to partially disassemble the gun and strike the valve stem with great force to manually exhaust some of the excess pressure.

The 140 ended this problem by having a valve that blows open violently when outside pressure is released by the trigger. Instead of having to be knocked open by a hammer, this valve is held shut by the trigger! It sounds easy to envision, but the details required to make it work took a lot of engineering.

One quirk of the blow-off valve design is that the trigger becomes progressively harder to pull as internal pressure builds. No doubt there's a way to fix this, but it hasn't come to market, yet, to my knowledge. The Japanese have refined the blow-off trigger to the greatest extent in their Sharp Ace Target rifles. They're very good, but not quite perfect.


The loading trough is simple, but just a bit crowded for longer pellets.


The 140 went through a series of modifications while it was in production, eventually morphing into the 1400 Pumpmaster around 1972. The new rifle began life with a sliding cover over the pellet loading trough in the receiver (you don’t have to cock this rifle--the action of pressurizing does it), but the final version had a more conventional bolt. It seems strange not having to cock a gun to shoot it, but 1400 owners quickly become accustomed to it.

Unfortunately, there IS a fly in the ointment! Because this gun doesn't require cocking--it's ALWAYS cocked! If owners keep one pump of air in their guns to keep the valve sealed against airborne contamination (almost every manufacturer recommends doing this), then their rifles will always be ready to fire! The 10 commandments of gun safety take on new meaning when you realized this gun is always ready to shoot.


Although it resembles the 160's adjustable trigger, the 1400 is far simpler.


Accidents are known to occur with this trigger arrangement. I have had my gun fire when putting the first pump of air into it. Another man was lucky that his rifle wasn’t loaded, because he examined his empty barrel from the muzzle end when his rifle had three pumps of air in the reservoir. It fired in his face! So, the sear CAN slip on these rifles, and shooters need to be aware of their special and unusual functioning.

Although the safety considerations above might frighten away prospective owners, they really shouldn't. Properly handled, the Crosman 1400 is no less safe than any other model; you just have to know what you're doing when you handle it.


Like most Crosman guns of the period, the sights adjust for windage by means of an oval slot and screws.


The sights have always been crude on this family of air rifles. The set on my rifle are a plastic post front and a simple leaf rear with a plastic notched elevator. Windage adjustment is made by sliding the rear leaf sideways, then clamping it down with a screw in an oblong hole. Accuracy, which is quite good, would undoubtedly increase by several orders of magnitude with more sophisticated sights.


The old Crosman "ashcan" pellets were marginal. Today's Crosman Premier (on the right) is considered to be one of the finest long-range pellets made.


I use 14.3-grain Crosman Premier pellets oiled liberally with FP-10 lubricant in my 1400. They seem to be about ideal for the rifle, although they weren't around when the gun was new. My rifle was one of the last to be made in the early 1980s, when Crosman pellets were still the soft lead "ashcans" that deformed in your fingers. All of Crosman's "golden age" airguns benefited from the better pellets of the 1990s.

Next time, I'll share velocities and more.

Monday, November 10, 2008

Hand pumps of antiquity - Part 1

by B.B. Pelletier

This 3-part blog is a reprint of my article in Airgun Revue #4.

With the current fascination for antique big bore airguns, hardly a thought is ever given to the equally old hand pumps used to fill them. Yet, without those pumps, the big bores could not have existed.

In the scant airgun literature that exists, you can read a few accounts of the performance of the old guns. In doing so, you'll encounter two very different viewpoints. The first are reports of people who have actually handled and fired vintage big bores. They describe how they performed and give estimates of power and accuracy that seem quite modest.

Then there are other articles written mostly from secondhand information. These are much more effusive in their descriptions of the performance of ancient air arms. What firsthand information they do provide is accompanied by very little hard technical data. Instead, they're full of subjective descriptions of what it feels like (or must have felt like) to shoot the old guns--guns that the authors may have never actually seen! That got me wondering.


The Barnes outside lock rifle.


Knifemaker and airgunsmith Gary Barnes is the one who really started me wondering. I saw the big bores he was making and listened to him talk about their actual performance in relation to the embellished tales he had read, until I, too, began to suspect much of what had been written. The outside lock rifle he made in 1998 seems to indicate a remarkable level of performance with very little air pressure. Yet, when the wick is turned up in the form of more stored air pressure, the performance goes down. It seems there's a specific window of good performance for every airgun, on either side of which lie negative returns.

If the guns of the past were so narrowly regulated by design, then their air pumps had to get them only into that optimum range. Greater pressure did not equal greater power; it actually upset a delicate balance of related components the guns need to perform at their best. So, when this relationship is understood, the performance of the antique pumps can provide clues as to the performance of the guns they serviced.


Two of the vintage air pumps made by Dennis Quackenbush. The larger one would be useful for rifles and shotguns. The smaller one would be for air canes. Not only is the size related to the amount of reservoir volume to be filled, the fit of the pump in the case with the rest of the gun and tools must be considered. Because of that, the handles and foot stands are made to be removed for easier storage.


I've seen vintage air pumps many times as parts of cased sets, but I never paid much attention to their construction. The assumption was that if anyone wants to charge an old gun today, they'll use CO2, which gets them up to as high as 900 to 1,000 psi effortlessly. Or, they could fill from a scuba tank or a modern high-pressure manual air pump like the Swedish Axsor. The antique hand pumps are just for show, aren't they? Perhaps not.

If we can establish the performance parameters of vintage hand pumps, then we'll also know the range of air pressures within which vintage big bores had to operate. When that's known, their power outputs can be calculated. Not exactly, perhaps, but it's certainly possible to estimate the ranges of power within which the guns must be performing.

There are several good reports on vintage airgun power outputs. But, woven in with them are the other reports that lack validity. These are the exaggerated stories that many people, including myself, have tended to believe and to repeat because they are the more spectacular accounts. With them go proclamations of accuracy and of killing power at extreme distances, all based on these dubious and unsubstantiated claims.

Before we proceed, let's look at another fantastic tale from the world of firearms to illustrate what can happen when facts are based on spectacular accounts. Legendary border patrolman and writer Bill Jordan was reported to have killed a criminal with a shotgun at a range of 100 yards. He was shooting 000 buckshot (.36 caliber shot), and one pellet was supposed to have hit the man in the head, if the story is true. Lethal, yes! Probable? No! No one doubts that the shot was anything but the wildest of flukes. Even if the report is not correct, the fact that it COULD happen is all that's important for this comparison.

If we accept an account like this, someone who read and believed it might well write another article about how such a shot was possible at even 125 yards. Then, some other writer would key on that and, before long, there would be claims of lethality at 200 yards for a shotgun blast. It's pretty ridiculous when examined this way, but that's what's been happening with big bore airguns for several decades, and no one has so much as raised an eyebrow. Until now.

In 1998 came the science of splatology. From Barnes' careful observations of recovered lead balls fired from big bores, a correlation was made between the size and shape of the recovered "splat" and the velocity at which it impacted. It's possible to determine impact velocity to within a narrow margin this way. The splats from the past, recorded by cameras and drawings, can thus be examined to reveal their impact velocity. It is, therefore, possible to deduce how fast those old guns were actually shooting--which turns out to be not as fast as some modern reports have said.

Still, splatology is not 100 percent conclusive proof. Balls going faster than 700 f.p.s. disintegrate entirely, leaving no record. There couldn't be any historic proof of those. Since a splat represents only the impact velocity, we still have to calculate how fast the projectile was going when it left the muzzle. But, a gun that shoots in the 550 f.p.s. realm is probably not likely to also throw one over 1,000 f.p.s. Although we've heard claims of very high velocities for modern big bores, we have yet to actually see one demonstrated. In our experience, it's been impossible, thus far, to reach such a speed with the big bore guns made today, to say nothing of the less efficient guns of centuries past. [Note: That statement was true when I originally wrote it, but modern big bores have progressed to the point that a few of them can now exceed 1,000 f.p.s. with light projectiles such as round balls.] By knowing the air pressure limits of vintage hand pumps, we have a big clue to the performance parameters of vintage big bores.*
----------
*Note: In the Fall of 1998, I fired a special Quackenbush Brigand rifle in .375 caliber that the maker had designed to operate on 3,000 psi instead of the normal air/CO2 combination valve that's usually in the gun. The combination valve operates best at pressures around 1,200 to 1,400 psi because it's set up to work with either air or CO2 gas; the 3,000 psi valve is optimized to that pressure alone. The 3,000 psi gun shot an 83-grain round lead ball through the chronograph at 893 f.p.s., making it the fastest big bore projectile yet tested by The Airgun Letter. This gun got four usable shots on a full air charge, but the first was the fastest and each successive shot was slower.
----------
One thing we know is that a pneumatic gun that functions well at one pressure level will most likely not do well at another. Therefore, if a big bore shoots 550 f.p.s. on a charge of 450 psi, it is unlikely to work at all when pressurized to 1,000 psi. We’ve known this about modern multi-pump pneumatics for many years. If you over-pump them, their velocity decreases until finally they cease to function at all. That's the point called valve lock. Why wouldn’t the older pneumatics, different in caliber only, work the same way?

In fact, there's no other way they can work! All pneumatics that use an impact-type valve will exhibit the same characteristics of an optimum performance window within a certain range of pressure. The window can be widened or even shifted by design, but there will always be an upper boundary. If there weren't, the potential energy of a pneumatic airgun would approach infinity, and we know that it doesn't. By knowing what air pressure was available to get behind the vintage big bore projectile, we can determine the energy window. And, we can find out the available air pressure by studying the pumps that created it. That's the thinking that went into this test.

Quackenbush's tests, methods and findings will be in future segments.

Friday, November 07, 2008

What to oil - Part 2
Oiling piston and breech seals

by B.B. Pelletier

Part 1

I will be gone next Monday through Thursday. I'm going big bore airgun hunting on an exotic game range here in Texas. I'm asking you veteran readers to cover me on the comments during that period. Next Friday, I'll reveal a big new product for you. It should be worth the wait.

I had completely forgotten about this series, but Stingray reminded me on Wednesday, so here's the next part of the lube story. This is a really important report, because much of airgun operation and efficiency depends on the right lubrication and I'm glad to record it in one place.

Before I begin, we have a new reader who has just purchased what he believes to be an unfired Beeman R1 rifle in .20 caliber. I invited him to come to this blog and promised to answer his questions about keeping his new rifle in top working condition. This report on lubrication will go a long way toward that goal.

Today, I'm going to discuss how to oil the piston seal and breech seal on spring-piston guns including breakbarrels, sidelevers and underlevers.

Different oiling categories
Spring-piston guns must be divided into several categories before a lubrication plan is put into practice. I'm not talking about how the gun is cocked (breakbarrel, sidelever, underlever or any other method) but how the powerplant is constructed. The age of the gun plays a large part in making the lubrication schedule, so let's begin there.


A sidelever (or underlever) rifle with the sliding compression chamber forward.



When the sidelever or underlever is cocked, the sliding compression chamber moves to the rear, exposing the breech for loading. But it also exposes the air transfer port, which is located at the bottom of that yellow breech seal in this photo. This is where you drop the oil when lubricating the piston seal on most sidelever and underlever guns.



Breakbarrels are simple. Just break open the barrel for loading and the air transfer port is located behind the breech when the barrel is closed. It's the front of the compression tube, as seen on this Diana 27.


If you absolutely cannot find the air transfer port, you can drop the oil directly down the muzzle with the gun standing upright. On most guns, the oil will flow straight through the barrel to the transfer port. Only a few, like the IZH 61, have a transfer port located 90 degrees to the axis on the bore.

Leather seals
Some airguns are bound to have leather seals, and the older they are the more likely leather becomes. Leather piston and breech seals need lots of frequent oiling. Many of the older guns are also lower-powered, so the oil can be petroleum-based, if you like. For a gun with a leather piston seal, I would oil the seal every time you shoot the gun if you only shoot it occasionally, or once every two weeks if you shoot all the time. Drop 5-10 drops of oil down the air transfer port and allow it time to soak into the leather. Then cock and uncock the gun without firing, if you can, to make the seal flexible. Often, you can hear the seal go squish when you do this.

At the same time, if the gun has a leather breech seal, drop two drops of oil on the seal and allow it to soak in. If the seal is synthetic, it doesn't need any oil. It will be oiled by the small amount of oil that's blown from the transfer port as the gun is fired.


That dark circle around the bore is a leather breech seal! It doesn't look very good (kinda flat), but with frequent oiling it still works after 40 years!


Synthetic seals
Guns with synthetic seals require far less lubrication. The best of them are the RWS Diana rifles whose piston seals are nearly self-lubricating. The worst are possibly the cheaper Chinese guns whose seals are made from softer synthetic and may need more lube to do their job. I'm talking about guns like the B3-1, not a Beeman gun made in China. On average, a single drop of silicone chamber oil every 1,500 shots or once a year is about all they require. You can double that time for RWS Diana guns. The oil goes down the transfer port, the same as for guns with leather seals.

Unique seals and special circumstances
Some target springers, like the FWB 65/80/90, have piston rings that require oil infrequently. Follow the owner's manual for these guns. Other target guns, such as the Diana model 6 and 10 pistols and the model 60, 65, 66 and 75 rifles, have synthetic seals that require very little oil. Older guns, such as the Webley Senior which are pre-WW II, have a beryllium-copper piston ring that needs more oil. A couple drops every month or every time you shoot the gun will do. These older Webleys also have a fiber washer that serves as a breech seal. Oil them like leather breech seals.

Another special circumstance is a gun that's been lubricated in such a way that it lasts for many years without any extra lubrication. When I lubed my Diana 27, I loaded the mainspring with white lithium grease. It continually wicks into the piston seal and keeps it lubed, and that's been happening for about a decade now. When I tune a gun with synthetic seals, I coat the compression chamber and seal with moly grease. A gun will last 5 years lubricated that way--maybe less with hard use. So take the advice the airgunsmith gives you when he tunes your springer.

There's a final special circumstance I need to describe for you. Some spring guns made in the 1970s--like the FWB 124, Walther target rifles and Diana target rifles and pistols, have a poor formulation for the synthetic piston seal. The piston seals in these guns can dissolve in minutes when they're oiled for the first time after a long dry spell. The symptoms are that the gun won't shoot a pellet out the barrel, and you'll find chunks of a dark yellow waxy substance in the barrel when they're fired. Those are parts of the disintegrated piston seal. Stop shooting and replace the seals immediately. The new seals you use will not do that.

Beware of older information
Beware of reading the older airgun catalogs. They contain instructions for more frequent oiling of synthetic piston seals because people were not yet accustomed to the longer intervals they really require. Consequently, they tell you to oil every 500 pellets and to use three drops or more, which is way too much for a synthetic seal.

I have purposely not covered any other lubrication for spring guns. That subject will get its own report, next.

Thursday, November 06, 2008

How many shots in a group?

by B.B. Pelletier

SavageSam prompted this report, but many of you have indicated an interest. The number of shots that should be in a group is determined by how confident you want to be that the group represents what the gun can do. Some people will argue that if the gun shot a particular group they don't need anything more because obviously that IS EXACTLY what that gun can do. Today, I'm going to try to explain why that is not the case.

It all comes down to statistics, specifically inferential statistics, which is the science of using a small number of data to represent a very large number. But don't worry, today's report isn't going to be about statistics.

"Here's a partial score - Cleveland 3."

Doesn't tell you very much, does it? You don't know who the other team is, or even what they're playing. If it's basketball, it's most likely very early in the game. If it's hockey, the game could be over. So, partial data isn't very helpful.

I can over-simplify this entire report in one statement. A sample size of 30 provides enough data to predict the outcome of a large number of cases to a very high degree of confidence. It doesn't matter how big your data set is; a sample size of 30 will give a very accurate picture of the entire population.

However, there are many problems--all dealing with the randomness of the sample. If, for example, you want to know the average height of adult men in the world and your sample is taken from just one tribe of Watusi, your results will be skewed toward the high end and utterly worthless. The Watusi are known to be the tallest people on earth, so the average height of 30 adult males might be 6 feet, 7 inches. That's probably taller than most of the readers of this blog. How the sample is taken plays a huge part in the reliability of the outcome.

Can we set that aside now? I just wanted to demonstrate that I know how samples can be skewed. Let's get on with the main discussion. How many shots should be in a group to give good confidence that the group represents the accuracy of a given gun?

Well, one shot is worthless for group size prediction. Do we all agree on that? One shot tells you very little about where the next shot is going. If that's true, why do many people adjust their scopes after firing a single shot? Because they do not understand how a gun works and how randomness plays into the problem.

Three-shot groups
Three shots is the next size group, and, as unbelievable as it seems - at least to me - there are gun writers getting away with publishing three-shot groups in their articles. There's even one gunmaker who provides three-shot groups to sell all his guns! They're beautiful groups, too. Very tight. When you see them you really believe the gun could shoot that well. But it can't. Not all the time, which is what a group is supposed to be telling us.

A three-shot group has just one application. When you're sighting in, shoot a three-shot group after every change to the sights. Then, adjust the sights from the center of that group. As far as I'm concerned, that's the one and only use for a three-shot group. Why? Because statistically it does a very poor job of representing how the gun shoots.

Five-shot groups
The next group size commonly used is a five-shot group. While it's just two shots more than a three-shot group, the probability that it represents how well the gun can shoot increases enormously. Is a five-shot group representative of how good the rifle can shoot? That depends on what YOU mean by how well it can shoot. I can shoot five five-shot groups that will average one size and another single 25-shot group that will be a different size. The 25-shot group is going to be larger than the average of five five-shot groups. Even though the number of shots is the same--25 in both cases--the way the groups are measured will enter into things and give two different answers. Also, because I averaged the five-shot groups, I skewed the results in a favorable direction.

So, is a five-shot group representative? Not if what you're trying to determine the gun's accuracy. If you're trying to show what size five-shot groups it can shoot, then it is representative.

WHAT?

Larger groups
Here's the deal. Five shots are only a fair predictor of accuracy. Ten shots are much better, but even then the prediction they give is not entirely reliable. Statistically, it takes 30 shots to approximate to a high degree of confidence the group size you will get if you shoot the gun 1,000 times. Twenty-five shots will group very close to the same size as 1,000 shots and ten shots will give a group that's close enough for most practical uses. Five shots will not.

With five shots, you get in the right neighborhood, but you cannot take your results to court. In real terms, that means a rifle that gives a five-shot group of one inch might give a ten-shot group of 1.4 inches and a 25-shot group of 1.54 inches. A 30-shot group from the same gun might be 1.61 inches and so might 1,000 shots. Do you see how it works? A three-shot group from the same gun might be as small as half an inch.

Who are you and what do you need to know?
There are people who absolutely must know the ultimate truth about everything, and then there are the majority of people who can tolerate a little slop for the sake of expediency. Statistics support the first group by telling them that there will be no measurable difference between 30 shots and 1,000 shots, so they don't waste a lot of ammunition trying to find out what just 30 shots will show. But even that much shooting is way too involved for anyone who publishes their results.

But sometimes there are very compelling reasons for knowing the absolute truth. Developers, for example, should want to know exactly how their product performs under normal conditions.

Expediency
Five-shot groups are often used in print, realizing that they do not represent the absolute final word on a gun's accuracy, but they do put us into the right neighborhood. Just like the EPA average mileages for a given model automobile may not represent the mileage for your car, a five-shot group might only be a rough guesstimate for accuracy. If you buy a gun that shoots half-inch five-shot groups at 50 yards you should get concerned when your gun shoots only 1.5-inch groups at the same distance, just like you should get concerned if your Toyota Prius gets only 15 mpg.


When I tested my USFT rifle, the best group of JSBs at 50 yards measured 0.335" c-t-c.


The ultimate in reliable data
Ten-shot groups are used whenever the goal is to publish defensible results. And 25- to 30-shot groups are used by developers, testers and anyone who wants their results to stand up to peer review. Three-shot groups should be reserved for scope adjustment, only, and never used as a predictor of a gun's accuracy.


Test target sent with the rifle shows 25 shots at 51 yards passed through a 0.663" group.


At this point in our discussion I could show you numerous ways of manipulating the data to represent anything you want to show. But I think most of you are aware of that possibility, so I'm not going there.

You can do something about these different group sizes when you see them in print. If you see a three-shot group, double the size to get the probable 5-shot group from the same gun. To convert a five-shot group to ten shots, multiply by 1.4. To convert a ten-shot group to 30 shots multiply by 1.15.

Please don't do the math on the two groups shown above and then write me to say that what I said about the difference between five shots and 25 shots did not play out that way. You will only confuse yourself. I know it didn't work out exactly as I described. What's missing is the CONFIDENCE you can have that the five-shot group is telling you anything worthwhile.

I will continue to show five-shot groups in my reports because of time constraints, which is the big reason most writers use them.

Wednesday, November 05, 2008

Walther Talon Magnum - Part 1

by B.B. Pelletier


Walther's Talon Magnum is the .177 version of the Falcon Hunter. This is a big air rifle!


I promised this report to John, who has waited patiently for it. The Walther Talon Magnum is a breakbarrel single-shot pellet rifle made by Hatsan for Umarex. It comes with a black synthetic stock, scope and mounts. There are open sights and the scope is not mounted on the rifle when you open the box, but the scope-mounting video will help you with that simple task.

The rifle comes only in .177 caliber, but for those wanting a .22 or .25, the Walther Falcon Hunter is the same rifle with a different stock. The rifle also has open sights for those who want them. They're a fiberoptic bead in front and a fully adjustable rear notch. The muzzle is enclosed in a synthetic brake that holds the front sight base.

The metal is finished a deep black, and the polish is better than matte. So, there won't be any reflections to disturb those covert hunting shots.

A big, heavy rifle
This is a very large air rifle. The photos don't convey that, but compared to this 49" airgun, a standard Winchester model 70 centerfire feels like a carbine. It's also decidedly muzzle-heavy. I think the .177 caliber has a lot to do with that, because most of the weight is in the barrel. The rifle isn't heavy for a magnum springer at 8.2 lbs., but the muzzle-heaviness will make many shooters think it is.

The power is rated at 1,200 f.p.s. for standard lead pellets and 1,400 for non-lead lighweights. I'll test that for you. The barrel is very stiff to open, reminding me of a Webley Patriot. You have to slap the muzzle to break it open. The rifle cocks with 50 lbs. of effort, though that could decrease a little with break-in. The bottom line here is that this is a large, heavy and powerful air rifle. Don't get it for plinking because you aren't going to want to shoot it more than 50 shots at any one time. Hunters will find this is a great way to nail quarry with a minimum cost.

Scope
With the rifle comes a 3-9x32 scope in rings, so it's ready to mount. Just attach the ring bases to the proprietary scope base on the rifle and slide everything back till it touches the scope stop plate. Tighten the two screws (one on each ring base) and you're done. The optics seem bright enough for general hunting and the eyepiece is adjustable for focus. Each ring's cap has two screws, so I'll watch to see if they can hold the scope under recoil. The scope base looks similar to a Picatinny because of the cross slots cut into it, but it's really a standard 11mm dovetail. The slots seem to have no purpose for any scope mounts we know about.

Another reason this Talon Magnum reminds me of the Falcon Hunter is that the stock adjusts for length of pull in the same way--by installing or removing up to three shim spacers between the stock and the rubber recoil pad. The rifle comes with the shims out, and the length of pull is still 15" so most of us won't be needing them. For those who ask, the stock sounds hollow.

Trigger and safety
The two-stage trigger is long and stiff, and the owner's manual doesn't list any adjustments. On the box it's listed as a single-stage trigger, but the one I'm testing most assuredly is not. There's a single screw on the plastic trigger blade, but I doubt it affects the pull. It may adjust the first stage travel, only. I'll weigh the trigger-pull during the velocity testing, but right now it feels like at least 7 lbs. The safety engages automatically on cocking and can be reset at any time with the rifle cocked or not. Because of the safety's central location, the rifle can be considered ambidextrous, even though the cheekrest is only on the left side of the butt.

Well, that's my initial assessment. It's a big gun and a near-copy of the Walther Falcon Hunter but in .177 caliber. The velocity should be right up there with the other superguns if it comes near the advertised numbers.

Tuesday, November 04, 2008

HW55 Tyrolean - Part 6
Adjusting the trigger

by B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5

There is a special sales coupon on the home page for all who intend to vote. Those who are eligible, please take advantage of living in a free country and let your vote be heard.

Today, I'm going to clean, lubricate and adjust the Rekord trigger of Wayne's HW55 Tyrolean. After that's done, the path will be clear to finish the tuneup.

Cleaning first
The trigger in Wayne's rifle has never been touched since it was shipped from the factory. I know that from the characteristic overuse of grease on all the parts. A Rekord needs very little lubrication and only on one critical spot. Since it's nearly impossible to get all the metal parts completely dry (and we don't want that, either), the miniscule bit of lube that remains on their surfaces is all that's required.


When a Rekord looks like this, you can be certain it hasn't been cleaned since leaving the factory.


Getting off the old grease isn't an easy task. Not only has it hardened in place, it's caused the metal underneath to corrode. This is very common on Weihrauch triggers. I scraped off the corrosion with a knife blade and applied Ballistol to neutralize the metal underneath.

This is where a parts cleaner would come in handy. Lacking one, I used Q-tips and paper towels, besides the knife blade, to remove the old grease.


After a lot of scraping, the parts cleaned up pretty well.


Then lubrication...
Once all the grease was off, I lubed the one contact point where the sear holds the piston latch lever.


The only real place to lubricate a Rekord is here (the parts seen through the round hole), where the sear holds the piston latch. To cock the trigger this way, press down on the back of the piston latch.


...And adjustment
Then it was time to adjust the trigger. I found the sear contact set far too deep, something I've never seen in a factory Weihrauch trigger. Normally, I advise against adjusting the sear contact screw, but this time I had to in order to get the trigger to break as it should. I also lightened the tension on the trigger return spring. I will wait to test it in the rifle, but it feels like it's breaking at a pound or a little less.


The Allen screw at the left of center is the adjustment for sear contact. It's part No. 52b on the Weirauch parts diagram. Screw it in (clockwise) to reduce the sear contact.


To test the sear engagement, cock the trigger by pressing down on the back of the piston latch. Then slowly squeeze the trigger until it releases. This is a two-stage target trigger, so there must be two distinct stages felt. The first stage must stop positively, then the second stage has to break cleanly with zero creep. A properly adjusted Rekord will do this as well as any trigger made.

This job took about an hour because I knew exactly what to do. If it was your first time, you'd want to spend about twice that long just to make sure you got it right.

Finally test the trigger
This part is now set aside for assembly into the tuned rifle. When it is in the gun, I will cock the rifle and attempt to bump the trigger off engagement several times, with the gun held in several attitudes. There's no safety on the 55 model, so the trigger has to do it all. We need to make sure it's safe under all conditions.

Monday, November 03, 2008

The air transfer port
Part 3

by B.B. Pelletier

Part 1
Part 2

In this third report on the air transfer port of a spring-piston air rifle, we'll look at the optimum port diameter. I actually have data from the Beeman R1 that Dennis Quackenbush converted to take different air transfer ports, and I have some data from my Whiscombe JW75 rifle that came with transfer port limiter screws. We'll look at the R1 data first.

Testing the Beeman R1
The ports I have for the testbed R1 range in size from a small (0.075") to large (0.160"). In my testing, I discovered that a port size of 0.110" limited the velocity available in the .22 caliber barrel shooting .22caliber Crosman Premiers by about 50 f.p.s., and a port size of 0.125" gave the highest velocity recorded. A larger port of 0.145" gave identical velocities as the 0.125" port, but 0.155" was about 20 f.p.s. slower. The optimum range of port sizes for a .22 caliber Beeman R1 falls between 0.125" and 0.145".


Dennis Quackenbush modified the compression chamber to accept these transfer ports. The blanks are for additional experimentation.


Switching to a .177 barrel on the same R1 and shooting  .177 Premier lites, the results were fairly close to the .22 barrel, except that the 0.110" port lost only 40 f.p.s. and the 0.155" port might have lost slightly more than 30 f.p.s. Because I was averaging a spread of 10 irregular shots, the numbers are not as close as I would like for a reason I'll mention in a moment.

The conclusion I drew from the test was that for the Beeman R1, a port size of 0.125" is ideal for both .177 and .22 calibers. That happens to be the size Weihrauch uses for that model. I would assume .20 caliber would also work well. Since only a few .25-caliber R1s were made, I'm guessing the factory left the port size at the same 0.125." That makes their job easier and also allows for the field swap of a different-caliber barrel without a major disruption.

But wait
Now for the downside. The transfer ports Dennis made leaked a little. They were a close fit in their hole in the compression tube, but they had no special provisions for sealing their outside diameters other than the closeness of the fit. It seemed that some air blew past the port on every shot. The velocity was about 50-60 f.p.s. slower in .177 caliber and 30-40 f.p.s. slower in .22 than an unmodified R1, but that's difficult to pin down since this testbed rifle can be fired only with a replaceable transfer port. Since no two rifles perform the same, it's a stretch to compare the testbed rifle to an unaltered R1. I don't know if this affected the outcome of the test.

A second test rifle
The Whiscombe that I made into a 5-part report also came with transfer port limiters that operate exactly the same as the replaceable ports Quackenbush made for the R1. They fit tighter, however, because the restrictors are Allen screws with air holes bored through their centers. The screw threads, being very close in size to the corresponding threads in the end of the compression chamber, offer greater resistance to escaping air than the straight sides of the Quackenbush ports.

Though I didn't do a test of comparative velocities per se, I did write in Part 2 of the report that the rifle it was shooting .22 caliber Crosman Premiers at well under 12 foot-pounds when I received it. When I removed the Allen screw transfer port limiter, the same .22 caliber rifle shot Premiers at 26.88 foot-pounds. You can also read in that report that the transfer ports of various sizes affected velocity much more than the Quackenbush ports on the testbed R1.

Evaluation of a third spring rifle
I also measured the transfer port of a Webley Patriot and found it to measure approximately 0.154". I say approximately because I didn't disassemble the rifle to take the measurement. Clearly, this port is much larger than an R1 port, but it had a strange affect on velocity. In .25 caliber, it worked well but in .177 caliber (Quackenbush sent me a Patriot with all four caliber barrels) it couldn't even break 1,100 f.p.s.! I found that shocking until I looked at the R1 test data. The .177 caliber did not like the larger ports there, either, so there must be a caliber relationship to port size.

Conclusions
This really isn't enough data to form solid conclusions, but it appears that as caliber increases, the transfer port size can also increase a little without power loss. And a smaller caliber can more easily tolerate a smaller port.

The second observation is that the port works best when it's the only place the air can pass through. Any blowby and the advantages of the perfect port size might be lost in the overall inefficiency of the rifle. That would include a weak breech seal.