Archive for March 2008

How to easily sight-in an air rifle

by B.B. Pelletier

This post was inspired by a Pyramyd Air customer who recently returned a LaserLyte boresight device because it was 5″ off his aimpoint at 30 yards. I was flabbergasted that he got AS CLOSE to the mark as 5″ at that distance! He thought he should be CLOSER?!

Laser boresight devices are supposed to align the bore of your rifle with the sight line of your sights. They can get your rounds ON PAPER at 100 yards! They ARE NOT supposed to zero your scope.

When I was in the Army, I used to boresight 105mm M68 cannons on M60A1 tanks, because the “paper” (actually a huge 12-foot square plywood sheet) sight-in target was 1,200 yards away. With those monster rifles, we didn’t have the luxury of shooting at a small target at closer distance. Our normal targets were positioned 1,500-2,500 yards away, so 1,200 yards was considered close. We used black thread in a crosshair pattern over the 4″ muzzle and binoculars to look through the barrel from the breech. When we fired, everyone on the range helped us by watching through binoculars to see where the tracer went. The inert aluminum practice round left a perfectly circular hole in the plywood. If you saw where it went, it was easy to see the resulting hole through a 10x scope. The ammunition was expensive, plus it wore the bore rapidly, so we didn’t want to shoot more than necessary. The goal was to hit within a 24″ circle at 1,200 yards and to take as few rounds as possible to get there.

With firearms, you may have to boresight
With a centerfire rifle, I may use some kind of boresighting method to get on paper at 100 yards, but not always. Sometimes, I start sighting-in on a 50-yard or even a 25-yard range just to make things easier. Because the target paper is closer, the bullet has a greater chance of impacting somewhere on it, especially at 25 yards.

On some days, the range is full of shooters and I can’t move between targets at different ranges. I have to sight-in wherever I happen to be. If I’m unlucky, I find myself on a 100-yard range with a rifle I’ve never shot and the target paper I’m shooting at is only 12″ square. Only dumb luck would get me on paper under that set of circumstances, so I’ll use a laser boresight device if I have one. Or, if the rifle is a bolt-action, I’ll remove the bolt and sight through the barrel by eye. When both the reticle and the bore seem to be pointing at the target, the chances are good the bullet will hit somewhere on paper. What if it doesn’t?

A field expedient for sighting-in
The best field expedient to get on paper at long distance is to pick a spot on the dirt backstop berm that you and a friend can both identify – you looking through the scope or open sights of the gun and your friend looking through binoculars. Aim at the spot and both you and your friend call where the shot actually strikes. Adjust the sights from there. If you hit low and to the left of the aimpoint, adjust the scope or sight higher and more to the right. As long as you can agree on the aimpoint, this should take just one shot, or two at the most.

But airguns are different
Airguns aren’t centerfire rifles. They don’t have more than a small fraction of the danger range, so they’re much easier to sight-in. You don’t need a boresight device; you just need a cardboard box and 10 feet of distance. Tape a small target with a dark central aimpoint to the box. At 10 feet, it doesn’t take much to get on a small piece of paper. I use 10-meter pistol targets that measure 8″Hx7″W. Except for a Bug Buster, no scope is clear at 10 feet, but that doesn’t matter, and the aimpoint is way too large, too. But, you can still see the aimpoint well enough to align the crosshairs.

If you don’t have real target paper targets, don’t use copier paper. It’s terrible. Use a piece of cardboard or tagboard that will leave a visible pellet hole. I used cardboard for the sight-in article I wrote. At 10 feet, you want your pellet to strike the target directly below the aimpoint of the scope. How far? By the height that the sight line of the scope is above the bore. The height of the scope above the bore determines how far below the line of sight the pellet will strike AT CLOSE RANGE. Sighting-in is the process of making these two lines converge at some distance. Think about that. If the muzzle were touching the target, that’s how far below the scope’s line of sight it would hit. Backing up to 10 feet just gives the scope a little chance to focus on the aimpoint. Then follow the rest of the directions in that article.

Special airgun problems
Sometimes, I’m not sighting-in a .177 – I’m sighting-in a .45 caliber big bore. And, I’m at the range by myself (I belong to a private range and I’m often the only person on all four ranges). You don’t sight-in a .45-caliber, 500 foot-pound air rifle at 10 feet!

I recently had this problem, and didn’t have time to start on the 25-yard range, so I used a 4-foot-square piece of cardboard cut from a flat-screen TV box as my sight-in target on the 50-yard range. Believe it or not, there were still problems hitting that big target square at 50 yards (I didn’t know what bullets shot well in the rifle I was testing), but I solved them by aiming at the extreme corners of the target cardboard. Finally, one shot printed about three feet low and three feet to the right. That told me two things – the bullet I was using was wrong for the gun, and I would need gross scope adjustments if I wanted to use it. That sight-in session failed because I couldn’t find a good bullet of the six types I had available that day. The next time out, I found the right one and got 1″ groups with it. The point is that sometimes you have to improvise. You couldn’t do what I did on a busy public range, but you could do the berm trick with a friend.

Sighting in airguns is a breeze, if you use the smaller scale of the guns to full advantage. Yes, it’s cool to have all sorts of high-tech gadgets in your range bag, but sighting in isn’t a high-tech exercise. Remember to play safe and always wear safety glasses, and your sight-in sessions will go on without a hitch.

Scopes – Part 4 The features you need & the ones you want

by B.B. Pelletier

Part 1
Part 2
Part 3

I have very good news. I was sent some pre-production samples of Leapers’ new RWS Diana scope base, and they look beautiful. I know the techs at Pyramyd Air will love this new base, which mounts to the rifle in seconds, solving both the droop problem and the recoil stop problem at the same time. I’ll report on them soon. Today, however, we’ll look at the features scopes have, in an attempt to sort out what’s really important from what’s cool or nice to have.

Starting with the scope
You want a scope that is both waterproof and nitrogen-filled. While most models sold by Pyramyd Air have both of those features, don’t think that all scopes do. The less-expensive scopes sold in discount stores and the cheap scopes available through some internet retailers and at gun shows may have only one or neither. Unless you shoot indoors exclusively, your scope will eventually get wet. I’ve seen shooters stop in the middle of a field target match because their scope fogged up on the inside and became unusable. One time, we were in a rainstorm that was on the fringe of a hurricane, and the misty droplets fell relentlessly. Over half the scopes in that match failed from internal fogging.

Another thing you want is a scope with strong erector tube springs. When you adjust very high or far to the right, the spring that pushes against the erector tube relaxes, and in some scopes the erector tube starts moving, causing POI shift. One reason I push Leapers scope so much is because they don’t do this. High-end Bushnells are okay, but the cheaper ones aren’t. The old Swift scopes had a problem with this, as did some of the Simmons, especially the inexpensive ones. And, as highly as they’re touted, certain Leupold scopes were problematic, as well. Especially the Vari-X II, which is a lower-end scope for them. I haven’t tested all scopes, so I don’t know how to tell you which ones are safe and which aren’t; but, if you feel the adjustment knobs going soft toward the high or right ends of the adjustment range, stay away from that part of the range with that scope.

Reticles
If you hunt, you want a duplex reticle. Nothing stands out so well against an uneven background of woods or grasses. If the hunting is slow-paced, a mil-dot reticle may be as useful as a duplex. Either type gives the benefit of multiple aim points.

Plain crosshairs are not suited to hunting, except in limited situations such as long-range varmint hunting. They’re also best for long-range target shooting.


A plain crosshair, while great on a firing range, isn’t as helpful in the field.


A duplex reticle stands out in uneven backgrounds such as a field or woods. The center still has the precision of narrow crosshairs.

Mil-dot reticles are very popular today and can be adapted to many kinds of shooting. They can help with aim-off for wind and for holdover for long distance. However, forget determining range with one. The formula is complex and the time it takes you will allow your target to move. The centers of some mil-dot reticles, though not the one shown here, are still a plain crosshair for precise aiming.


The mil-dot reticle is very popular and common today. They’re almost as useful for hunting as duplexes.

There are many other reticle types, but none are as useful as these three. Some look like the landing pattern for a commercial airliner and are so confusing that they offer no real benefit, except to the curious.

Illuminated reticles
Illumination is great for hunters and for anyone who loses sight of the reticle against the background. Before you decide, know that there are two different kinds of illumination. The first kind reflects off the reticle and is the brightest. This is the most common type of illuminated reticle, and the whole reticle is illuminated at the same time. A second type is more subtle and not as bright but appeals to the true fringe-time hunter. That’s the central illuminated reticle in which only the center crosshairs are lit. There’s no loss of night vision with this type, but you have to be in very dark surroundings to see it. The key to this type of illuminated reticle is an etched-glass reticle.

When the illumination isn’t turned on, the reticle is black, the same as non-illuminated reticles. So nothing is lost by having the illumination feature. But for general shooting, it is useless. I wouldn’t get illumination unless there is a need for it, or the scope you want only comes with it.

Adjustable objectives
AO, as it’s known, is for parallax correction, though most shooters think it’s for focusing the scope. When you adjust the objective (or the sidewheel that I’ll mention next), the target becomes clear at some point. At this point, there’s as little parallax as possible, and the shot should not be affected by it as long as your eye is going to the same spotweld every time. AO is extremely valuable and should always be ordered with a scope, if possible. The cost is minimal and only the really cheap scopes or those of very low magnification do not have it today.

A sidewheel
Let’s get something straight – a sidewheel refers to parallax correction that has been moved from the objective bell to the left side of the scope turret for convenience. Some illuminated reticles have their intensity adjustments in that location, but that does not constitute a sidewheel, regardless of what their advertising may say. The benefit of a sidewheel parallax adjustment is that you don’t have to reach as far to make the adjustment. This is a nice-to-have feature when it is offered.


A sidewheel refers to parallax correction, only. Large sidewheels like this make small yardage increments visible for the shooter.

Return-to-zero adjustment knobs
Some scope knobs can be unlocked and their scales slipped to whatever point the shooter desires. The rifle can be sighted-in, then the adjustment knobs can be set to the zero numeral on the adjustment scale. This feature will appeal to careful shooters who document everything about their gun and scope. But for those who do not, nothing is more confusing than a return-to-zero scope adjustment knob if you move it, because you will forget where you came from. The return-to-zero (also called zero locking) function is for shooters who keep careful notes. Most shooters do not need it.

Variable power
Variable power used to be a bad thing, but today it’s good. It’s hard to buy a scope without it, and you can rest assured that all the bugs have been worked out. Get it if you can. You can operate at one power most of the time, or you can adjust power to find the target, then zoom in for an accurate shot. If you buy a variable, get one that goes low enough. High power can make your target appear hazy or muddy, but lower power will make it crisper. Scopes that go down to only 8 power are destined for field target or benchrest work. That’s too much power for many shots in the field. In my opinion, the best variable is a 4-16x, with a 3-12x coming right behind.

Why do we collect airguns?

by B.B. Pelletier

I was reading the Yellow Forum recently and happened across a comment by an acquaintance of mine, Ted Summers. After his comment, he quoted something I wrote in the second Airgun Revue. I’d like you to see it, too:

Some day, every airgun in your collection is going to belong to someone else. You only “own” them for a brief period, and then they’re on the block again. Don’t fret about this – it’s how you got them in the first place. Think about it.

There’s a lot to ponder in that statement. For some reason, that’s exactly what I have been doing for the past few weeks. I look at what I have and wonder why I have it. At some point in time, each gun was important to me, but as I look them all over, many have faded to the background. So I have to ask myself: Why do I own them?

My first collection
I own 8 nice Daisy No. 25 pump BB guns, and I know why I do. When I was a kid, I bought a 25 for $5 from my sister’s boyfriend. It was a wonderful 1936-type engraved gun with lots of deep bluing and great power. But several days after I bought it, the power went away. In desperation, I disassembled the gun partway – for reasons I cannot fathom, because what was I going to do after that? My parents were against me owning BB guns, so I didn’t feel they would be sympathetic to this problem. After creating a basket case, I sold it to a friend for a quarter just to get it out of my life. Two days later, he returned with the gun assembled and shooting powerfully again. He told me his father put it back together then showed him how to oil the piston seal to make the gun shoot hard. That was insult heaped on my injured pride!


The No. 25 pump gun is one of my favorites, but I sure don’t need 8 of them. At the top is a 1913 first-model, followed by a 1914 second-model. Third gun down is a transition gun from 1916-1918 and the bottom one is a 1930 model.

So as an adult, I have an attraction to the No. 25 pump gun. I’ve learned as much about them as I can, and I’ve tuned a couple in the process. Now I look at the 8 in my collection and see redundancy. I don’t need or even want all 8 any more. I’ll take a couple of them to airgun shows and sell them or trade for something I do want. The others I’ll keep, because that old wound is not completely healed.

Odd gun becomes an obsession
Another gun in my collection is a Kruger cap-firing BB gun from Wamo. Actually, I own two of them, and I’m in pursuit of the Western Haig pistol I wrote about last week. Wamo made that one, too. These aren’t even airguns in the strictest sense, because they use caps to propel the projectile. In a very distant way, they’re actually firearms!


The Kruger ’98 was Wamo’s idea of cleverly suggesting a Luger without copyright infringement. It used toy caps to propel either a BB or .12 caliber lead shot (they came in both calibers).


Western Haig wasn’t sold under the Wamo/Wham-o name, but the owner of Wamo held the patent on the gun.

My mother bought me a Kruger as my first BB gun. You can read about it here. It was a horrible failure as a gun, but it stuck in my mind like a homely classmate you can never quite forget. After I started writing about airguns, I became aware that Wamo also made a .22 rimfire single-shot pistol called the Powermaster. Then, through my airgunning friends Bob Speilvogel and Richard Schmidt, I discovered that Wamo also made two other different .22 rimfire guns they probably never advertised. When I contacted Wham-o (they now go by that spelling, but they’re the same company) to ask about the history of the Powermaster, they denied ever making it and insisted Wamo must have been a different company.


Wamo Powermaster was one of three different .22 rimfire firearms made by Wamo/Wham-o.

That transparent lie (which I can prove) lit a fire under me! As I researched the Powermaster, it became clear that no one has ever researched this story or documented many of these guns. Now I’m on a quest for information about the history of the company and about the six firearms they made (including the Krugers and the Western Haig). I’m compiling my research into a large article for Shotgun News this fall. I guess the point in this case is that you shouldn’t lie to a writer! And, I will not be parting with any of my Wamo/Wham-o guns in the forseeable future.

The unloved as well
Just as there are guns I cannot part with, there are others that leave me cold. I once owned a beautiful HW77 that had been tuned to a gnat’s eyelash. It was a rifle of which I was very proud. Then I got a TX200 that legendary tuner Ken Reeves tuned for me. It did everything the 77 did…just a little better. I let the 77 go. At the time, I said I didn’t need two perfect rifles. Then I got a TX200 Mark III that topped my Reeves-tuned Mark II and the Mark II went away. So, in the case of fine underlever field target rifles, I guess there is only room for one in my heart.

When I add up the 10-meter target pistols I have owned, people might get the wrong impression. I have at one time owned two FWB 65s, two Walther LP IIIs, A Walther LP 53, a Diana model 10, a Drulov DU-10, an IZH 46 and a Chameleon. Only the 46 and the Chameleon remain, and I keep them because I can compete with either one. The others were great collectibles, but not up to the task of a full 10-meter match for one reason or another.

I know collectors whose whole lives are wrapped up in their airguns, but I’m not like that. I do live to shoot, and I get to sample a lot of different airguns and firearms in the process, but it takes a special bond for one of them to stay with me. Perhaps the strongest attraction I have is to a gun that has never been reported, or to one that’s tied to my youth in some way. I suppose the attraction is different for everyone, but each of us has some compelling reason why we select the airguns we do.

This report was written especially for The Big Bore Addict, who’s now putting his collection together.

RWS Diana Schutze – Part 1 New youth breakbarrel rifle

by B.B. Pelletier


RWD Diana Schutze is a beautiful new youth-sized breakbarrel.

I asked for this rifle and RWS USA responded. The RWS Diana Schutze breakbarrel is an answer to my prayers for more and better youth-oriented spring rifles. I get emails every week from parents asking which model air rifles are suited to their kids. There are a few good ones at present, but the number has slipped over the past 20 years. With the magnum craze going full-bore, airgun manufacturers have taken their eyes off the youth market, yet that market is important for several reasons. First is the fact that we can never have too many good airguns for young shooters. They will probably stick with the shooting sports if they have early success, and a quality air rifle is just the ticket for that. But, there’s another, less-obvious reason that’s even more important.

Adults like ‘em, too!
The market may be red-hot for testosterone-laden, supersonic, magnum spring rifles, but think of youth guns as the minivans of airgunning. Everyone uses them without comment. Long after the bragging rights have worn thin on that super-blaster, the shooter will remember a gentle shooting air rifle with a smile. Beeman sells the R7 on that premise. There were a lot of wonderful spring guns competing for honors in that category back in 1985; in 2008, the choices are fewer. Enter the RWS Diana Schutze.

The name game
This rifle may be new here in the U.S., but the model has been in production since the 1990s. On the rifle, it says model 240, which is the current version of the model 24. When Diana dropped the models 23, 25, 27 and 35 in favor of the models 34, 36 and 38, the models 24 and 28 were also created. The model 28 is a more powerful rifle than the obsolete model 27 and the model 24 was a smaller, lighter rifle. It is supposed to be almost as powerful as the 27, though its size is between a 23 and a 25.


The name Schutze is not on the rifle. It’s the model 240.

Technical
I measured every one of the specifications I mention here. They may not be the same ones you see online. The Schutze is small in almost every way. The total length is just 40 inches, yet the pull is an adult-sized 14.25-inches. It will feel like a lightweight carbine in adult hands. The barrel measures exactly 16 inches. The rifle weighs just 6 pounds and cocks with 21 pounds of effort. I’d like to see that cocking figure reduced to 15 lbs. or less, but it’s a number I can live with. The ball-bearing barrel locking detent is stiff and will require a slap to open initially, but it’ll wear in and become super-smooth.

Trigger
The trigger is not adjustable. It’s two-stage with pronounced creep in the second stage. The pull is stiff, breaking at around 6 lbs. While that sounds heavy, remember this rifle is intended for young shooters, whose trigger fingers aren’t always as disciplined as they should be. No doubt, it’ll become smoother and lighter with use, but never too light. The specs say 5 lbs., which sounds about right.

An automatic safety is set every time the rifle is cocked, no different than any other Diana spring rifle. The safety button comes back from the rear of the receiver, so it’s a snap to take off with your thumb when grasping the rifle to shoot. It can also be reset at any time (cocked or not) and simply blocks the trigger from moving.


Safety sets when the rifle is cocked. Note the lack of a scope stop on the 11mm dovetail scope rails.

Stock
The beech stock is slim in all dimensions, which adds to the handy feeling the little rifle evokes when you hold it. The buttpad is a solid black rubber pad that keeps the rifle in place when it’s stood in the corner. The wood is stained a medium-to-dark brown and is finished smoothly all over. There’s no checkering, and the shape is completely symmetrical, making this model 100 percent ambidextrous.

Sights
The front sight is a hooded post with a red fiberoptic bead at the top. It sits atop a molded synthetic ramp with side vents for style. The whole assembly is attached permanently to the barrel and cannot be removed. With target lighting, the front sight bead goes dark, becoming a perfect square post.

The rear sight is a square notch with green fiberoptic beads on either side of the notch. Unlike the front, they do not go dark with target lighting and will continue to frame the front post in all light. The rear sight adjusts in both directions with crisp click detents. There’s a scale for the vertical adjustment wheel, but none for the horizontal.

There’s a scope rail, but it has no scope stop provisions. I’m recommending to RWS Diana that they drill and tap a hole for a simple mechanical scope stop, because shooters today tend to use scopes over open sights.

I was very happy to see this rifle at this year’s SHOT Show and asked to test it as soon as possible. Right after IWA (the European SHOT Show) finished in mid-March, the gun was sent to me. I plan on putting it through its paces because we really need more good youth guns. Adults are demanding them!

Running target

by B.B. Pelletier

Before we start, I’m getting lots of questions about shimming breech seals for breakbarrels. One of you should write a guest blog about it.

I promised this post to Derrick several months ago. Today’s the day!

History – Running Stag, Running Deer
Running Stag dates back at least to the mid-19th century, when the target was a wooden stag (a male chamois) with a target attached in the place where the stag’s heart would normally be. The stag was mounted on wheels and pulled along a track.

The setting was outdoors, and the track was positioned between two dense bushes. The stag was pulled along the track as fast as a normal stag might run and the goal was to put a bullet in the animal’s heart as he passed in view. The standards for this sport seem variable, but there was a special venue in Munich, where it was practiced in the 1860s, so at least the course of fire was always the same.

In England, the sport was called Running Deer, and it was practiced with pretty much the same rules at the same time. The sport was still a local or possibly regional one at this time.

History – Running Boar
Running Boar came much later, probably from Prussia, and the target was a two-headed boar that had a set of scoring rings printed over a colorful lithographed paper or painted wooden target. The target was shot as it passed by in both directions – left to right and right to left. The target went both slow and fast. Men got 30 shots (15 in each direction) at the slow target and 30 at the fast target, for a total of 60 shots. Women got 20 slow and 20 fast.


This is half of a Running Boar target. This would be the half you shoot at when the target crosses from right to left. This is a modern American target printed on target paper. The vintage Running Boar targets were boars on brightly lithographed colored cardboard game scenes or brightly painted wooden targets.

Running Boar has been shot with centerfire rifles as well as with .22 rimfires. The trend in modern times is toward the rimfires because the required range facilities are smaller and the range safety fan is reduced. I believe there was even a scaled-down running boar target for air rifles, but there’s an even better event now: running target!


Thie full-sized Running Boar target looks like this

Running Boar has been shot with centerfire rifles as well as .22 rimfires. The trend in modern times is toward the rimfires because the required range facilities are smaller and the range safety fan is reduced. I believe there was even a scaled-down Running Boar target for air rifles, but there is an even better event now – Running Target!

Running Boar requires a range setup that is fairly permanent, so if a facility has invested in one, they tend to leave it up and running. As a result, the sport tends to weather long periods of low popularity. Similarly the rifles are specialized equipment and are not well-suited to other sports or general use. So if one owns a Running Bore rifle and has access to a working raqnge, one tends to stay with the sport.

Running Target
Running Target is strictly an air rifle sport. It made it into the 1992 Olympic Games, but was dropped after 2004. It’s still a World Cup event. Without the Olympics as a goal, the luster is off the sport. There is a world championship title, however.

The target is just that – a normal bullseye target. Two bullseyes are printed on a page with an aimpoint between them. This allows passes in both directions. The old sport of shooting at a moving target didn’t change, but the target did, and now there’s a specific aimpoint. The number of shots and the fast and slow presentations remain the same as for Running Boar: 60 shots for men, 40 for women.


The AR-6 Running Target looks like this. It’s two 10-meter bulls with an aimpoint in the middle. The target passes just like the Running Boar.

The Running Target carrier is still a mechanical system that presets the target across a two-meter gap at 10 meters. It runs in both directions at two different speeds. The target is visible for 5 or 2.5 seconds, respectively. The mechanism is very expensive, so not many clubs or individuals will buy them. This has limited the sport to some extent.

Want to try it?
The Gamo MTS 1000 Moving Target System lets you shoot at moving targets with airguns. The deer target has two heads that reset appropriately, depending on the direction the deer is moving. The system is made from light-gauge metal, so it’s most appropriate for airguns of lower velocity – not unlike 10-meter target guns. A Daisy 953 would be ideal with this target. It wouldn’t be exactly like Running Target because there’s no scoring target, but you would get the same kind of training.

Beeman SS1000H Dual-Caliber rifle combo – Part 8

by B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7

This is an unprecedented 8th look at the Beeman SS1000H Dual-Caliber rifle. Farmer asked me to test the .22 caliber rifle holding its zero following a barrel change. I also wanted to put 100 Beeman Kodiak pellets through the rifle to exercise the lip of the parachute seal (Aren’t you glad you know what THAT is?), so this test accomplished two goals at the same time.

A quick recap
Thus far, we’ve seen that this rifle is very accurate and powerful in .177 caliber, and it’s also accurate and powerful in .22, but there are some velocity variance issues. The Beeman Kodiak pellet was accurate when tested before, so it worked out well that I could use it in this test. I’ve mounted a Bushnell 6-18×44 scope in place of the one that comes with the rifle, because that one isn’t clear at 21 yards, which is the range at which I did this test.

Very hold-sensitive
I wanted to shoot several groups before the barrel change, as well as after, to show what happens, if anything, so I concentrated on my shooting style. I burned through about 30 shots trying different holds, then another 30 trying to see if Gamo Hunter pellets would work (they didn’t). I won’t bore you with the details of the hold I finally settled on; but, I’ll say that if you own this rifle, plan on spending a lot of bench time figuring out how to best hold it.

Before changing the barrel
I spent real time trying to settle in with the best hold. The fact that it took real time, in my eyes, makes the S1000H a very sensitive rifle. I test airguns all the time, and I can usually figure out one pretty fast, but this one was daunting. However, once I realized it was that sensitive, I became much more careful and started getting the results I was hoping for. Because this is a test for potential group shift, I wanted at least two groups in the same place before removing and reinstalling the barrel.

Every group is shown in the same orientation at which it was shot.


This group of five Kodiaks was the best of the whole test.


The second group before the barrel was removed and reinstalled is larger but in the same place.

Now, the barrel was removed and reinstalled to simulate changing calibers.


This is the first group, and you might be inclined to believe that the zero never changed if this was the only group you saw after barrel installation.


Whoa! That’s not a group – it’s a pattern! This second group after the barrel change is huge and not in line with the accuracy we know this rifle has.


The third group after the barrel change is tighter than the second, and can you see the shift in the POI?


Group four after the barrel swap is tighter, and the POI has definitely changed.


Group five after the barrel swap proves that I’m human and don’t always get good groups. This group is more or less in agreement with the previous target, though twice as large. And, the POI has changed from where it was before the barrel was removed and reinstalled

Oh boy! We’re gonna get comments about this test, aren’t we? “Why does the rifle act that way?” “That’s exactly what MY rifle’s doing!” If this is exactly what your rifle is doing, and you haven’t changed your barrel, you have a rifle that’s very sensitive to how it’s held. That means sensitive to where each finger touches the stock and whether you relax before shooting and on and on….

If your rifle does this AFTER changing barrels – well, that’s what they do! Only in Hollywood can a sniper unpack and assemble a rifle and hit his target with the first shot. It doesn’t work that way in real life.

In this month’s American Rifleman,¬†they tested a Knight KP1 combination gun that comes with a rifle barrel, shotgun barrel and inline muzzleloading rifle barrel. A brief quote from one caption in that article tells the whole story:
In minutes, the KP1 can be fitted with an in-line muzzloading barrel, a shotgun barrel or a center-fire barrel. Zero isn’t an issue as sights and scopes are barrel-mounted

So I’m not making this up – zero really is lost when you change the barrel on a rifle. Not just on this rifle but on any rifle with interchangable barrels.

Finally pcp4me tells me he was told by a Beeman tech that Beeman SR-series rifles have leather seals. Since he posted that remark to the dual-caliber blog post, I think he meant Beeman RS rifles, of which the SS1000H is one. If that is the case (the SS1000H having a leather seal), there should be a simple fix for the velocity variation. Simply heavily lubricate the piston seal with corn oil. A long time ago, I was told that corn oil builds up a residue in the uneven compression chambers of spring-piston guns, making them far more consistent. I will try this fix and report back to you.

Spring piston seals

by B.B. Pelletier

Yesterday, TC told me he wasn’t familiar with what a piston seal looks like. I linked him to the 13-part “Spring gun tune” report, but nothing in that report really explains a piston seal, so today I thought I’d do that.

History
The first piston seals were simple, flat, leather pads screwed to the end of a steel piston. They worked but weren’t too efficient. Around the turn of the 20th century, the cupped leather seal was born. The cupped end faces forward and fills with air as the piston rushes forward. The air inflates the leather cup, driving its sides against the compression chamber wall. That gives a better seal than a flat leather pad.

Piston rings
In the middle of the century, there was a brief use of metal piston rings as seals. They work exactly as they do in a car, sealing the compression chamber by expanding into the wall. They had several drawbacks. First, they are precision metal parts and cost a lot to make. Second, because of their location, the volume ahead of the piston is not as small as it would be if the seal were located on top of the piston instead of around the side. For this reason, piston rings are reserved for low-velocity airguns.


Piston from pre-1940 Webley Senior pistol has a beryllium-copper piston seal that looks like a automotive piston ring. When the piston is inside the gun, the ends of the seal are pressed closed. Pardon the grease, but I’m not about to relubricate my pistol for anyone. It will still work fine 25 years from now.

Teflon
Teflon is a synthetic with a low coefficient of friction. Also, it squashes and holds its shape, so companies like Weihrauch and Webley have experimented with it as a piston seal. It works well in the HW 45/Beeman P1. You fit this seal by dry-firing the gun several times. It simply squashes to fit the cylinder. No lip is possible because of the squashing nature of the material.


The Beeman P1 has a Teflon piston seal. This is the top or front – the side that faces the air transfer port. No lips are required because Teflon squashes to fit the compression chamber.

Parachute seals
The synthetic parachute seal is best seal of all. It can be fitted to the compression chamber so it drags very little; but, when it goes forward, the lip of the seal inflates and expands against the compression chamber wall just like the old leather cup.

There are many variations on the shape of the parachute seal, but they all do the same thing – expand against the compression chamber wall to seal the air in front of the piston. When you oil the piston, you help the seal do its job, because the oil fills in all the microscopic scratches on the piston wall. But, the oil also burns, so over-oiling causes detonations that can ruin the piston seal and mainspring.


This is a Beeman Laser piston seal that was part of the laser tune they sold for the R1. It’s a classic parachute seal because of the lip that blows out into the compression chamber wall. This one’s been fitted to my rifle. Because of the synthetic material in the seal, a special grease called Laser Lube was used with this tune. The round impression in the seal is from the air transfer port, made by the piston slamming into it several thousand times.


Vortek experimented with several R1 piston seals in the 1990s. I tested this one along with several others. It doesn’t have a typical parachute lip, but the flange around the top serves the same purpose. Note the V section on top was perfectly centered on the air transfer port.


The famed RWS Diana blue synthetic seal is one of the longest-wearing and most self-lubricating piston seals on the market. They often need fitting to the gun by thinning the sides of the parachute lip. They also require very little lubrication.


These two Chinese piston seals from the 1990s are examples of “Monkey see, monkey do.” The Chinese copied the parachute design without understanding it. The result was these colorful seals made from synthetic ticky-tacky that were totally inappropriate for the job intended. They don’t do well in airguns, but they look good enough to eat! The Chinese have since learned their lesson in seal-making.


The legendary FWB 124 was one of the first airguns to use synthetic parachute piston seals. Unfortunately, they used the wrong formulation material, which disintegrates over time. These are totally useless, having turned to the consistency of hard wax over the years. Modern replacement seals for 124s are made of much better stuff.

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