Archive for May 2005

Synthetic-skirted (saboted) pellets and accuracy

By B.B. Pelletier

Today’s posting is an answer to a question from one of our readers:

I heard saboted pellets don’t work very well in some airguns because of the barrel being choked. Is that true?

Can a synthetic skirt be accurate?
I can only give you my personal observations on this question, plus the scant material I’ve read and seen. I’ve not had good luck achieving the same level of accuracy using pellets with synthetic skirts (what our reader and some manufacturers refer to as sabots) as I have with homogenous, pure lead pellets. Ten years ago, synthetic-skirted pellets were not very accurate at all. They were relatively new to the airgun scene and certain manufacturing problems I’ll discuss in a moment weren’t properly addressed.

Top-quality synthetics are better today
Today, the picture has changed greatly. Top-quality synthetic-skirted pellets are now very uniform, and accuracy has improved quite measurably. That said, there are still some brands of synthetic-skirted pellets that do not measure up to the high standards of the makers I am going to mention. Therefore, what I’m about to say only applies to the specific brands I mention.

Prometheus was a pioneer
Prometheus was an early developer of synthetic-skirted pellets. Initially, they marketed their pellets as the fastest pellets on the market, because, indeed, with the combination of their light weight and their low-friction synthetic skirts, they proved faster than any lead pellets around. But that nearly sank the company! They caused British spring guns that had been below the legal UK limit of 12 foot-pounds to suddenly exceed it!

Accuracy was such an issue with the early synthetics that Prometheus did a huge amount of R&D to correct it. The problem resides in the two-part projectile. A synthetic pellet is made from a hard metal core and a lightweight synthetic skirt that surrounds and contains the core. Unless the pellet is very uniform, it will not be accurate. It’s more difficult to marry two dissimilar parts, the core and the skirt, into one than it is to form homogeneous lead into a precision projectile.

Prometheus finally made an accurate saboted pellet!
Prometheus persisted and by the late 1990s they had a pellet that was very consistent. They even made a promotional video showing shot groups with large numbers of pellets going through very respectable groups at decent distances of 25 yards and more.

Skenco pellets are very accurate!
I’ve tested almost all of the different types of saboted pellets made by Skenco and found them to be very accurate. They’ve got quite a variety to choose from, including some long-range .177 pellets heavy enough for some of the more powerful springers.

In the final analysis, I must say that top-quality homogeneous lead pellets are more accurate than synthetic-skirted ones. It isn’t because of the choke at the end of the barrel, but because of the two-part construction of synthetic pellets compared to more uniform lead pellets.

Tokyo Marui VSR-10 G-Spec MG315

By. B.B. Pelletier

Tokyo Marui may make the finest airsoft guns in the world, but they aren’t real good at naming them! The VSR-10 G-Spec MG315 is REALLY a military sniper rifle, that looks a lot like the U.S. Army’s M24. Based on the Remington 700 bolt-action rifle, the M24 is a wonderful rifle for sniper duties and our subject gun is perfect for airsoft players.

It’s so SMOOTH!
If Marui ever needed a poster child for quality, this is the one. This spring-piston gun is butter-smooth. The ease with which it cocks is forgotten when you squeeze the trigger and note the calm shooting behavior. If pellet rifles could be made this smooth, people would buy them – I don’t care what velocity they had! It’s a shame that many players will feel the need to beef up the powerplant, because they will no doubt say adios to such smooth behavior as I have never seen in a spring airgun.

The magazine works like it should!
The magazine inserts in the bottom of the stock and fits flush with the rest of the stock when it’s all the way in. A special magazine loader comes with the gun, or you can load it manually, one BB at a time.

Feeding was flawless, though the gun has a decided preference for Marui 0.20-gram BBs. The Hop Up mechanism on the left side of the stock is easy to adjust, allowing you to change ammo brands and weights quickly.

Other stuff that comes with the gun
A spin-on silencer completes the gun. Of course, there’s nothing to silence on the Marui; but on the firearm, the silencer muffles the report to keep the sniper’s location hidden.

A Picatinny-type rail attaches to the receiver for scope mounting. It looks great, plus it holds your optics rock-solid. This gun is accurate enough to warrant a scope. Expect to hit inside an 8″ circle at 50 yards (off a rest, of course) and a full-torso silhouette at 90 or even 100 yards should be possible once you get things dialed in.

Marui puts non-detachable swivels on the gun, but the studs that anchor them are what you need for detachables. A set of QD sling swivels from any gun store (or Wal-Mart) is just the trick.

Best feature of all, this rifle is light! By the time you get a scope, sling and bipod mounted, you’ll be pushing 7-8 lbs., which certainly beats the 12 lbs. of the real deal. After a day on the game field, you’ll thank Marui for the weight savings.

The manual has some English it in! Though most of the instructions are in Japanese, there is enough English to get along. As always, the illustrations are very good.

For long-range sniping in airsoft games, this Marui is worth a look!

More on muzzle velocity and energy

By B.B. Pelletier

I received the following question posted as a comment to my May 18 posting, What about Eun Jin pellets? I thought this question deserved a better answer than just a few lines in the comment section, so here it is.

Question:
I keep noticing the reference to foot-pounds of [energy] when talking about the force needed for certain ammo. All airguns I read about are usually rated in muzzle f.p.s., or I see a reference to calculating foot-pounds with a particular round.

Do airguns have an “unloaded” foot-pounds-of-pressure [rating] to go by?

I ask because I purchased a Winchester 1000B from Pyramyd Air, and I cannot find a reference to its foot-pounds. Wonderful weapon, by the way.

Answer:
The foot-pounds of energy that an airgun is capable of generating is related to its muzzle velocity in this way: muzzle velocity X the weight of the projectile = muzzle energy. There’s more to the formula than that, and it has been addressed in Tom Gaylord’s article Airgun formulas and other neat stuff – How to calculate foot-pounds and velocity.

Your air rifle shoots pellets of different weights at different velocities. So it delivers different muzzle energy as the weight of the pellet and its initial velocity changes.

Airguns have a RANGE of muzzle energy
A gun doesn’t just have one muzzle energy rating. It has a range of energy produced with different pellets. An “unloaded” energy rating for any airgun would take into account the expected range from the lightest to heaviest pellet.

Some pellets are too large for the bore and don’t go as fast as their weight would indicate, while others are too small and don’t seal well, resulting in velocity lower than expected. So, instead of a clean graph of energy that changes with the weight of the pellet, we get a graph that has a few surprises in it.

Let’s experiment
Let’s plug in some numbers and see what happens. On your own Winchester 1000B, let’s say you’re getting 713 f.p.s. with 10.6-grain Beeman Kodiaks. The energy calculator in the article says that would give you 11.97 foot-pounds of muzzle energy. The lightweight RWS Hobby pellet that weighs 7 grains would have to go 855.17 f.p.s. to match that energy, but when you shoot them in your gun, low and behold, they average 901 f.p.s. That’s an energy of 12.62 foot-pounds.

Speed up with synthetic pellets
If you want to shoot even faster, try the Hyper velocity lead-free sabot pellets, type 2 in your gun. At 5.9 grains, you might expect them to go 950 f.p.s., but the plastic skirt has such a low coefficient of friction that they actually go 1,011 f.p.s.! Wow! According to the energy calculator in the article, you’re getting 13.39 foot-pounds!

The bottom line
What we’ve seen in this hypothetical experiment is that your Winchester 1000B air rifle has an energy spread of 11.97 foot-pounds to 13.39 foot-pounds. No airgun has a single muzzle energy or velocity, but each possesses a range of energy and velocity depending on the pellet used.

I used the velocity provided by the manufacturer (1,000 f.p.s.). But since I don’t have your rifle to test, I don’t know how exact that is. My velocity figures for the pellets mentioned are in the ballpark for rifles with the Winchester 1000B’s power range. For actual figures, chronograph your gun with each pellet.

Are longer barrels more accurate?

By B.B. Pelletier

How long must a barrel be to be accurate?
There is no answer to that, because short barrels are JUST as accurate as long barrels. That’s today’s post in one sentence.

I just overheard an airgunner asking his buddy how much more accurate he thought a longer barrel would be for his AirForce Talon SS. As I listened, the two of them hypothesized about all sorts of accuracy influences that don’t really matter or even exist.

Proof that a longer barrel doesn’t increase accuracy
You can explore the accuracy versus barrel length controversy right here on the Pyramyd Air website. Let’s start with a look at the Drulov DU-10 target pistol and the Drulov DU-10 Eagle target rifle. The rifle has a barrel twice as long as the pistol, yet there is NO discernable difference in accuracy. The rifle has a higher velocity as a result of a longer barrel, which means it can shoot farther than the pistol, but it does not group any better at 10 meters. Both are made for 10-meter target shooting and both are equally accurate.

A longer barrel guides the pellet for a longer time, so it MUST be more accurate. Right?
No! When it comes to accuracy, the length of TIME a pellet stays in the barrel is inconsequential. The belief that longer barrels are more accurate might harken back to the days of the Kentucky rifle, when barrels were very long. They got that way to more effectively burn their charge of blackpowder. A side benefit was the increase of distance between the front and rear sight. That made for more precise aiming, which in turn led to greater accuracy. But, the longer barrel, by itself, was no more or less accurate than a short barrel.

Need another example? Here it is. The barrel of a TX200 is less than 10 inches long, yet that rifle is one of the most accurate spring-piston rifles in the world. The TX is legend among field target shooters, who often choose it above every other spring gun made. Yet, it has one of the shortest barrels in the world of spring guns.

Swap barrels on your Talon SS & accuracy stays the same!
Back to where we began. The Talon SS provides the best way to prove this question because you can change barrels in a very short time. AirForce offers a 24″ .22-caliber barrel for the Talon and the Talon SS (and in .177). The Talon SS comes with a 12″ barrel; while the longer barrel increases velocity, the accuracy remains the same. According to AirForce, all three models group about 1″ at 50 yards with any length barrel in either caliber.

A man who proved short barrels are deadly accurate!
Elmer Keith was a famous shooter who wrote a lot about long-range handgun shooting. He’s famous for killing an elk at 400 yards with a handgun, a shot that proves extremely difficult for a marksman rifle shooter. During a demonstration for the U.S. Army, he once shot an entire magazine of Colt .45 Automatic from a government M1911A1 pistol through a man-sized silhouette at 200 yards. Most soldiers find it difficult to hit a man-sized target at 25 yards with the same gun! So, short barrels never bothered Keith!

By following Keith’s instructions, I once shot several cylinders from a snubnosed Colt Agent .38 Special in front of witnesses through a football-sized target at 80 yards. So, there you have it. Long barrels, by themselves, are not more accurate. They may help by increasing the distance between the front and rear sights, but the sheer length of the tube has no bearing on how accurate the gun will be.

Warm weather means hotter velocities for CO2 guns!

By B.B. Pelletier

Shooters in Florida, the Southwest and Hawaii don’t worry much about cold weather, but the rest of us do because the winter puts an end to outdoor shooting with CO2 guns. Now that summer is back in almost every corner of the US, all of us can head outside again for loads of powerful CO2 shooting!

Many of you may already know that warm ambient temperatures can increase velocity in a CO2 gun. How? Because CO2 evaporates at higher pressures as the air temperature increases. As the air temperature increases, CO2 is warmed and more pressure is achieved inside the CO2 container. And, as you know, higher pressure means more power!

Did you know that barrel length also increases velocity? Let’s take a look at a CO2 pistol that demonstrates this perfectly.

How to get an extra 110 f.p.s. from a pistol
The velocity for a .177 TAU 7 Match pistol is 450 f.p.s. The same gun with an extra two inches of barrel – the TAU 7 Silhouette – gets 560 f.p.s. It’s amazing that just adding length to this barrel – with no other functional changes in the gun – will make a pellet go 110 f.p.s. faster!

A longer barrel means compressed gas has more time to accelerate a projectile because the released gas is escaping in an enclosed environment – between its source and the pellet. Because it is captive, the gas is channeled into moving the pellet forward. Once a pellet leaves the barrel, it immediately starts to slow down. Since the gas is pushing the pellet for a longer period of time (an extra two inches, in the case of our TAU pistol), it is giving it that much more speed. So, you can choose between higher gas pressure (when temperatures are warmer) or a longer barrel to increase velocity in your CO2 gun. What if you combined these two? You’d extract the maximum velocity from your gun!

Another trick to get the most velocity from your CO2 gun
To get even more velocity from your CO2 guns, simply pause for a longer time between shots – at least 30 seconds is good in cooler weather. In the hot summer with the sun shining, a pause of 10-15 seconds is all it takes. The gun cools down with the shot because CO2 acts as a coolant. By allowing it to warm up again, you’ll gain extra power.

Warm weather safety for CO2 guns
There is a limit to how hot a CO2 gun or container should get! If you leave a gas gun or container in a closed car on a summer day, it can explode! At the very least, it will blow the seals out of the gun; at the worst, it could remove your windshield or even injure somebody. CO2 containers not enclosed in the gun could also explode. Be very attentive whenever a gas gun is exposed to temperatures above 80 degrees F. If that means exhausting the gas from the gun or the container, then do it. That’s better than an accident.

Bad vibes

By B.B. Pelletier

Today we’ll look at a problem some spring guns have in abundance – too much vibration!

What causes vibration in a spring gun?
Vibration is caused when the moving parts of the powerplant have too much clearance. The moving parts include the piston with its seal, the mainspring, the spring guide and sometimes other parts – such as the piston liner (inside the piston), which removes some of the clearance between the mainspring and the piston wall. Technically, this last part isn’t supposed to move, but if it gets bent during operation it can cause vibration.

Do powerful guns vibrate more?
More power isn’t really an indicator of a tendency to vibrate. In fact, some very powerful spring rifles hardly vibrate at all. Gas-powered piston guns, such as the Beeman RX-2, are among the smoothest, as far as vibration is concerned, though it may take a little time to get used to the quicker recoil.

You might even expect a powerful steel spring rifle like the Webley Patriot
to vibrate a lot, but it doesn’t. Yes, you will feel some vibration, but compared to other spring guns, it isn’t too bad. Now, RECOIL on a Patriot is a different story!

Webley and BSA know how to tame vibration
In my experience, both Webley and BSA spring rifles have been the most vibration-free airguns. Weihrauch guns usually vibrate more, and they also vary more, gun to gun. Most older Chinese airguns are pretty bad, but for some reason the newer ones are very nice. I think the Chinese have learned a lot about fitting powerplant parts in the last 10 years.

Gamo guns vibrate in the beginning and then become smooth!
Most new Gamo rifles I have shot seem to vibrate a lot. That said, you can significantly reduce the vibration just by continuing to shoot a Gamo rifle! It seems to take thousands of shots, but a well-used Gamo can be fairly smooth. Of all the Gamos, I find the Shadow 1000 to be the smoothest out of the box, though the Hunter 1250 Hurricane is surprisingly smooth, despite the power. The Hunter 220 has the most vibration of the Gamos I have tested.

Why would a formerly smooth gun now vibrate?
When a smooth spring gun all of a sudden starts to vibrate, it usually means the mainspring is canted (bent). Springs cant for a number of reasons, which I’ll cover in another posting. However, I will tell you now that there is no grease that can stop a canted spring from vibrating. The only solution is to replace the spring.

There’s a lot more to vibration than what I’ve written here, so look for more info in future postings.

The BB pistol that didn’t shoot BBs

By B.B. Pelletier

We’re surrounded by hundreds of BB pistols today. There seems to be no end of models from which to choose, but it wasn’t always that way. In the 1930s, the first American BB pistol was a very different kind of airgun.

The Daisy Targeteer was on every kid’s wishlist!
Daisy’s Targeteer was initially offered in 1937. It came in a cardboard box with the pistol, instructions, a metal tube of special shot (we’ll get to that in a moment) and spinner targets. The box converted into a backstop that held the spinners so they could be shot safely. All this cost just $2.00!


The first Targeteer was blued & had fixed sights.


The Targeteer box doubled as a shooting gallery.

Special shot for a special gun
The Targeteer’s action is a spring-piston design that has to be the world’s weakest BB gun! Instead of shooting conventional steel BBs, it shot special .118-caliber steel shot that Daisy made just for this gun. If you read about the Sharpshooter rubber-band catapult gun in my May 11 posting, you’ll remember that they are the same caliber as the Targeteer. The Sharpshooter shot traditional No. 6 lead birdshot that’s used in shotgun shells. The Targeteer’s ammo was steel! Only a company as large as Daisy had the resources to make a steel version of this shot!


Regular BBs dwarf the tiny Targeteer shot.

The Targeteer operates just like a conventional Daisy rifle in all ways but cocking. To cock it, pull the barrel back into the action. Most people simply pushed the muzzle back with the heel of their hand while holding the grip in their other hand, which means they’re cocking a gun with they’re hand over the muzzle!

Not a bang but a whimper
The Targeteer discharges with an anemic sound, much like a mouse coughing. When the piston jumps forward, the BB exits the muzzle at, perhaps, 100-150 f.p.s. Being very light as well as slow, the BB cannot break windows, lightbulbs or even one sheet of paper at a distance greater than 10 feet. That’s why the cardboard box was good enough as a backstop.

Even though this gun lacks power, it’s fun to shoot! The Targeteer lasted up to World War II, then resumed production after the war. Nickel-plated versions (often mistakenly called chrome-plated) were available after the war, as was a very pretty plastic shooting gallery model that housed the gun on top of the gallery when not in use. The gallery was only offered from 1949 through 1952 and is considered a prized Daisy collectible in its own right.


A fancy shooting gallery also held a
nickel-plated Targeteer when not in use.

Targeteers are easy to find!
I find Targeteers all the time at flea markets, gun shows and airgun shows. A reasonable price for the first-version blued gun by itself in good condition with lots of blue and no rust is $60. Nickel-plated guns with lots of finish sell for $40 to $60. A Targeteer complete in the cardboard box sells for $100 to $150; the red plastic shooting gallery with gun goes for $200 to $300, depending on condition. The metal shot tubes bring $5 to $10; if you’re lucky, they’ll still have some copper-plated steel shot inside.

Read about it in the Blue Book of Airguns
The Blue Book of Airguns, 5th Edition will be available soon. If you’re interested in strange old airguns like the Targeteer, be sure to order a copy.

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