Posts Tagged ‘Crosman Premier pellets’
by Tom Gaylord, a.k.a. B.B. Pelletier
It’s taken me awhile to get back to this pistol because I injured my hand, so I couldn’t fill the Hatsan AT P1 PCP air pistol from the hand pump for a couple of weeks, but last Friday I was at it again — probably for the last time. You may remember that I discovered that the AT P1 likes a fill pressure of 3,200 psi — which is sort of ironic in light of several recent reports I’ve done. This time, I used the Hill pump to fill the gun to that pressure to see if there are 10 good shots on a fill. That was the problem before — the circular clip holds 10 pellets, but the gun didn’t seem to want to shoot more than 7 of them on a single fill of air.
I decided that instead of wasting time with a lot of different pellets, I would concentrate on the one good pellet that I knew gave the best accuracy. That’s the Beeman Kodiak. First, I filled the gun to 3,200 psi, then loaded the clip and inserted it into the gun. Someone asked me how I held the gun to shoot it, given that it’s scoped with a Leapers UTG 3-9X40 AO rifle scope. The eyepiece has to be held within 2-3 inches of the eye in order to see the image. There’s a way to hold the gun that uses the scope as one of the handles, and that’s what I did. I photographed it for you, so you can see it as I describe the hold.
I hold the back of the scope at the eyepiece and let my hand separate the rear of the scope from my sighting eye by the required distance. My hand is pressed against my safety glasses to maintain the separation. The weight of the pistol rests directly on the bag, so all my other hand does is keep the pistol steady. With this hold, I can squeeze the trigger without moving the gun.
This hold is one I learned while shooting the LD Mark I pistol from Tim McMurray. That’s a Crosman Mark I Target pistol that Tim converts to add a longer bafrrel, a CO2 tank hanging down from the grip and a rifle scope mounted on top — just like this one. With the LD, I rested the external tank on my chest and held the scope like you see here. That gave me near-rifle accuracy.
The result is a steady hold — especially when you consider I’m shooting only 25 yards. I don’t recommend holding a recoiling firearm pistol this way, but you can get away with it on a PCP.
All targets were shot at 25 yards. The first target looked very good until the final shot. I could see that the pistol was grouping low and to the left, but all I was interested in was the size of the group. It could always be moved later with a simple scope adjustment. The group that formed looked very encouraging until the last shot, as I said. I could clearly see that one go high and into the center of the bull, ironically enough. But when I walked downrange to examine the target more closely, it wasn’t as good as it had seemed. A line of four shots appears to the right of the main group, and they’re strung vertically up to the center of the bull. The last one is the highest one. I never saw the other 3 shots in the string, so they could have been any of the preceding 9 shots. All I could see through the scope was the large group that formed at 7 o’clock on the edge of the bull.
I guess this first target took the wind from my sails. It was no better than any of the previous targets shot with this pistol. My idea that a higher fill pressure would keep 10 shots in a tighter group was bogus. But I still had time on the range, so I thought something else was in order. I adjusted the scope higher and to the right just a little, to correct for where the Beeman Kodiaks had grouped. Then, I loaded the gun with 10 JSB Exact Monster pellets. The Monster pellet weighs 25.4 grains, making it even heavier than the .22-caliber Beeman Kodiak. And it’s a JSB. I wondered if this might be the pellet that turns things around for the AT-P1 pistol.
Alas, it wasn’t. It turned things around, all right, but not for the better. The pellets were all over the place! In the end, 10 of them printed a group measuring 1.933 inches at 25 yards. It’s more of a full-choke shotgun pattern than a group shot from a rifled barrel!
Now, I was really downhearted. I switched back to the Kodiaks and give them one final try. The gun was, again, filled to 3,200 psi, and 10 more pellets went downrange. This time, the results were not as good as the first time. Ten pellets made a group that measured 1.211 inches between centers. It was higher on the target and also centered better, which proves my earlier statement that the group can always be moved by adjusting the scope, but things were not getting better.
Outcome and final evaluation
I put a lot of time and energy into testing the Hatsan AT-P1 pistol. The reward was not worth the effort, in my opinion. While I agree that Hatsan does know how to make a fine precharged air rifle, the AT-P1 pistol is not as refined as the rifles they make. It’s too large and too coarse for what it delivers. I wanted it to succeed because there aren’t that many nice PCP pistols to choose from, but the test results do not live up to the hope.
I think that if you’re interested in an airgun like thi,s you should look at the AT-P2 pistol, which comes with a shoulder stock. That way, you won’t have to learn how to hold the gun like I did here. As long as you know how few shots you’re going to get on a fill of air (7) — and you manage that, you’ll be fine.
by Tom Gaylord, a.k.a. B.B. Pelletier
Crosman’s 116 bulk-fill pistol is a .22-caliber single-shot pistol.
Today, we’ll look at the velocity of the Crosman 116 .22-caliber bulk-fill CO2 pistol. A couple things will complicate this test. First is the fact that the pistol has adjustable power. I’ll account for that with several power adjustments, but that isn’t all that’s going on.
The bulk-fill process is itself somewhat complex; because if the bulk tank doesn’t have enough liquid CO2 in it, or if the tank and the gun are both warm, the fill will be less dense and will therefore produce fewer total shots. Let’s look at the fill process before we examine the gun.
The bulk-fill process
Filling an airgun from a bulk tank requires that the filling tank has sufficient liquid CO2 inside to transfer the maximum amount possible to the gun. When I say the maximum amount possible, I mean what’s maximum under safe operating conditions. It’s possible to overfill a CO2 tank or gun and create a dangerous condition.
CO2 pressure is controlled by the ambient temperature rather than by compression. If you make the CO2 storage vessel volume smaller somehow, you don’t compress the gas inside. Instead what happens is more of the gas condenses into liquid. It will continue to do so right up to the point that there’s 100 percent liquid inside the tank.
While that sounds good, it isn’t; because when the liquid inside the tank heats up, it tries to expand into gas again. As long as there’s space inside the tank for the liquid to evaporate into gas, you’re safe; but when the safety volume is filled, all the liquid CO2 can do is increase in pressure. It does so at an astounding rate, quickly developing over 10,000 pounds per square inch at temperatures that are still well within human tolerance. That’s why tanks rated for CO2 storage contain safety burst disks to prevent the tank from becoming a dangerous bomb. It’s also why several airgunners have been startled when their tanks’ burst disks actually burst while stored in their cars on hot days. Once the burst disk ruptures, all gas is lost and the burst disk must be replaced before the tank can be used again.
These days, most airgunners get their bulk tanks filled at paintball stores; but in my day, they filled them at home. There were even larger bulk tanks of CO2, holding 20 pounds of liquid. They came from the food and beverage industry, or they were large fire extinguishers. I own 2 of these 20-lb. CO2 tanks that I use to fill my bulk CO2 tanks for guns.
The 12-oz. paintball tank is coupled to the 20-lb. CO2 tank for filling. This big tank has a siphon tube, so only liquid escapes the valve when it’s in the upright position. Couplings are custom made for this.
Once the smaller bulk tank has been filled, it’s time to fill the gun. Remember, the object is to transfer as much liquid CO2 as possible for a dense fill. That doesn’t give more power — it gives more shots. The CO2 controls the pressure, depending on the ambient temperature.
The 12-oz. paintball tank is then coupled to the CO2 gun like this. With the CO2 tank hanging down, the liquid in the tank is just behind the valve, where it will flow readily from the tank into the gun. This paintball tank has a special adapter with a wheel to control the opening of the valve.
Filling the gun takes just a few seconds. It actually makes a sound, and you can tell when it’s full because the noise of the transfer stops abruptly. The outside of the gun may become cold and wet with condensation when the new CO2 inside evaporates to gas. As long as you do this transfer at room temperature, everything will be safe, for the liquid CO2 will evaporate and stop the fill before the gun accepts too much liquid. The gun is now full and ready to test.
Because the pistol has adjustable power, I tested it on high power first. I found that there were 21 good powerful shots with the gun set on the highest power. Then, I adjusted it to medium power and finally to the lowest power. Medium power was very close to high power in all respects, but on the lowest power the total number of shots per fill increased to 32.
This is a Crosman gun, so Crosman Premier pellets sounded like the best place to begin. On high power, they averaged 390 f.p.s. The range went from a low of 384 to a high of 409 f.p.s. At the average velocity, this pellet generates 4.83 foot-pounds at the muzzle.
On medium power, they weren’t much slower — averaging 386 f.p.s. But on low power, they averaged 331 f.p.s. for an average 3.48 foot-pounds of energy.
Next, I tried RWS Hobby pellets. In .22 caliber, these weigh 11.9 grains and average 423 f.p.s. in the test pistol. That’s a muzzle energy of 4.73 foot-pounds. The low was 413 f.p.s., and the high was 435 f.p.s. On medium power, Hobbys went an average 402 f.p.s.; and on the lowest power, they averaged 369 f.p.s. That’s good for a muzzle energy of 3.60 foot-pounds. On low power, the low velocity was 355; and the high was 383 f.p.s.
The last pellet I tried was the RWS Superdome. This pellet weighs 14.5-grains in .22 caliber and is a favorite among many airgunners for all 3 powerplants. On high power, Superdomes averaged 376 f.p.s. The low was 362, and the high was 391 f.p.s. At the average velocity, Superdomes generated 4.55 foot-pounds. On medium power, they averaged 367 f.p.s.; and on low power, they averaged 345 f.p.s. On low power, the low velocity was 341, and the high was 348 f.p.s. At the average velocity, they generated 3.83 foot-pounds of muzzle energy.
The trigger-pull on the test pistol measures 4 lbs., 2 oz. That’s a little heavy, but it’s very crisp, so it’s going to be okay for target work. There are no provisions for adjustment on this trigger; so if I want to change the pull, I have to do some gunsmithing.
I noted that when the gun was fully charged, the velocity always started lower and climbed into the good range — just like a precharged gun that’s overfilled. On the lowest power, the gun sometimes failed to discharge. CO2 guns aren’t supposed to do that, so I assume either the valve return-spring has weakened over the past 60 years, or someone has been inside the valve and changed things. Either way, that’s a good reason for an overhaul. The transmission sealer worked and now so does the gun; but it doesn’t work exactly as it should. That’s also probably why the number of shots per fill was lower than expected.
To what can I compare this air pistol? How about to a Crosman 2240, which is also a .22-caliber single shot but runs on 12-gram CO2 cartridges, but in many other ways is like the test pistol? The 2240 has a 7.5-inch barrel, so it’s a little faster than this 116 with a 6-inch barrel (Premiers averaging 448 f.p.s. to the 116′s 390 f.p.s.). Its sights are fully adjustable. The grip, while a bit larger, feels very much the same. So, if a 116 and bulk-filling aren’t in your future, know that there’s a good alternative.
I do think the test pistol is shooting a little slow for a 116. Maybe it would be best to get it overhauled to see what one in top condition can do
by Tom Gaylord, a.k.a. B.B. Pelletier
This test was done for blog reader GunFun1, who asked to see what effect barrel length has on velocity. Though it appears simple, this test took 2 days to conduct because of barrel changes and other sundry things. But what was learned far exceeded my hopes, so the effort it took was well worth it.
I tested with an AirForce Talon SS, which has the facility to accept interchangable barrels. All testing was done with the rifle in .22 caliber, which means every barrel used was that caliber. I used the factory-installed 12-inch Lothar Walther barrel, an optional 18-inch Lothar Walther barrel and an optional 24-inch Lothar Walther barrel.
I fired 5 shots at each power level with each barrel. I could have shot more; but since I know the stability of the Talon SS powerplant, it really wasn’t necessary. And fewer shots made the test go faster. After every power change, I fired one shot before testing to settle the valve at the new level. I know that’s necessary for the Talon SS. Other PCPs may have different techniques after making power adjustments — including no warmup shots at all. But the SS requires one shot after every power adjustment. After testing each barrel, I refilled the gun to 3,000 psi. The pressure remaining in the reservoir when I began each fill was about 2,600 psi. So for all shot,s the rifle was running right in the middle of the optimum power curve.
I started each test on the highest power, then dialed back as the test advanced. That meant that when I got back to power settings 6 and zero, the rifle was in the middle of the power curve and was at its most stable condition.
I used only a single type of pellet — the 14.3-grain Crosman Premier. Had I used additional pellets, there would have been different velocities. The relationships we’re looking for are revealed in this one pellet as well as if I’d tested greater numbers of pellets. There was no need to waste shots or air.
I filled the air tank to 3,000 psi, then shot 5 rounds on the highest power, then 5 at power setting 10, then another 5 at power setting 6 and finally the last 5 at power setting zero. After every power adjustment, one dry-fire shot was taken to set the valve at the new power setting.
First, let’s look at what happened with all 3 barrels at the maximum power setting. The 12-inch barrel gave an average 835 f.p.s. The 18-inch barrel averaged 921 f.p.s. and the 24-inch barrel averaged 1024 f.p.s. That’s all with the same powerplant, the same amount of air being used with each shot — in fact, everything was the same except for the length of the barrel. This is a clear demonstration of what a longer barrel can do for a precharged gun.
However, there’s one thing we need to note. The barrel I used for the 12-inch barrel is not the same 12-inch barrel that was used in the previous test of rifling twist rates. If you look back at that test, you’ll see that this same rifle shot a Premier pellet on power setting 10 (854 f.p.s.) faster that it did in this test (827 f.p.s.). The reason is probably due to small differences in the individual barrels — the smoothness and diameters of the bores and how well the backs of the barrels seal against the air valve in the reservoir. So, one 12-inch barrel can be different than another 12-inch barrel — even when they’re both produced by the same manufacturer! That’s worth noting. I used to see this all the time when I tested guns while I worked for AirForce, and now I’m showing you what I used to see. A lot of shooters don’t understand or even believe this can be possible. They think that one barrel must be exactly identical to another barrel of the same specifications made by the same manufacturer.
A second thing to note is the fact that the 12-inch barrel didn’t get much more from the maximum power setting than it did on power setting 10 (835 f.p.s. to 824 f.p.s.). In fact, that held true up through the 24-inch barrel, which tells me that power setting 10 is about as high as I need to go to get the most from this particular rifle’s powerplant. Other PCPs that have adjustable power will behave differently than this, but they’ll all have settings that get the most effective use of their air. Anything more than that is just a waste.
Now, look at power setting 6 across all 3 barrels. The velocity increase as the barrel lengthens is smaller with this power setting than with the higher settings. Also, look at the 12-inch barrel between setting 6 and setting zero. That’s where the bulk of the adjustability for this powerplant is when that barrel is installed. But with both the 18-inch and 24-inch barrels, the useful power adjustment range extends all the way up to power setting 10.
Finally, power setting zero had a surprise. The 12-inch barrel was the fastest of the 3. That can be explained by more friction in the other 2 barrels, but it doesn’t explain why the 18-inch barrel was slowest and the 24-inch barrel was faster. That’s one of those anomalies you sometimes see when you test things like this.
I also want to say that the rifle became quieter with the 18-inch barrel, but got noisier again with the 24-inch barrel. You Talon owners don’t have the shrouded barrel the Talon SS owners have, but apparently your barrels are doing a great job of quieting the shots all by themselves.
Of course, all of this was made possible by the use of a chronograph. No amount of listening to how long it takes the pellet to hit the hickory tree from the back door will give you results like these.
A word from Edith
As many of our readers know, this blog was originally started on the Blogger site/software, and they’re listed in the right-hand column as the Historical Archives. Those blog posts are being moved to this site from Blogger so everything’s in one place. As originally planned, the comments to the old blog would have been lost. Due to the diligence of several of our blog readers who gave me links to help pages that showed how comments could be transferred along with the posts, we’re not losing anything!
The transfer process is almost complete, and the old blogs/comments will soon be available on this site. One caveat: Blogger posts didn’t have categories and tags when this blog first started, and we didn’t start using them when that feature was added later. So, in my spare time (imagine hysterical laughter at this point), I’ll be categorizing the old posts and creating tags that will help you find related items quicker than if you had to do an ordinary word search.
by Tom Gaylord, a.k.a. B.B. Pelletier
This test is being done because in Part 3, the accuracy test, I felt the scope I was using wasn’t giving the Hatsan AT P1 PCP air pistol the best chance for success. It was a vintage Weaver K856, which means a fixed 8x magnification with a 56mm objective lens. Though it doesn’t say anywhere on the scope, I’m pretty sure the scope’s parallax is fixed at 100 yards. At the 25 yards I was shooting, the target was slightly blurry.
The best group I got in that test was five Crosman Premiers into 0.678 inches at 25 yards. That was shooting off a sandbag rest with a rifle scope.
I said at the end of that report that I would return with a different scope mounted and try again, and today is a report on how that went. The scope I selected this time was the UTG 3-9X40 AO True Hunter that hasn’t hit the market yet. It’s a full-sized rifle scope with a suggested retail price of $104.97, so I would expect to see it sell for something less than that. I’m not going to report on this scope in detail today, but you do need to know that it’s a fine scope for this test. The parallax adjustment worked perfectly, and I was able to get the target bulls into sharp focus. The way I had to hold the pistol to use the scope was a detractor, but it’s no reflection on the quality of the scope, itself. I plan to do a full report on just the scope, but I’ll mount it on one of my rifles of known accuracy.
As I reported, the Hatsan pistol has a proprietary quick-disconnect fill probe that isn’t compatible with other airguns outside the Hatsan line, so I attached it to the hose on my Hill pump. I need my carbon fiber tank for filling all my other PCPs that are universally compatible with the Foster-type quick-disconnect fittings, so the Hill was dedicated to this pistol. It took 26 pump strokes to fill the pistol after 10 shots were fired. That’s 2.6 pump strokes per shot. I said in the last report that the gun seems to give the best results with 7 shots per fill; but since the clip holds 10 pellets, I shot it 10 times per fill. All of today’s groups are 10-shot groups at 25 yards. I feel that’s only reasonable because nobody wants to stop shooting and fill their gun in the middle of a clip.
Shooting was off a sandbag rest, which is fine for a PCP. This pistol does recoil a little when it fires, but that’s well after the pellet has left the muzzle of the gun. The recoil is more of a rocket-like push than a typical firearm recoil, and it’s far from the violent jump of most spring guns.
I overfilled the pistol the first time. I couldn’t clearly see the gauge on the pump and wound up putting 3,500 psi into the gun, rather than 3,000. So, just this one time, I shot 20 rounds on a fill instead of just 10. Had my groups been great, I would have gone back to the chronograph and looked at the velocity again with a 3,500 psi fill.
The Hill pump is great because it allows for such a fill. Other hand pumps peak at 3,000, but the Hill keeps right on going to 3,500. I bought it from Compasseco (which is now owned by Pyramyd Air) years ago when I was testing several BSA and BSA-made derivative PCPs because they’re all pressurized to 3,350 psi.
JSB Exact Jumbo Heavys
The first group fired was 10 JSB Exact 18.1-grain Jumbo Heavy domes. The scope was not sighted in, and the group landed about 4 inches below the aim point and 2 inches to the right. It measures 0.844 inches between centers. While that’s not much better than good, it beats all but 1 of the groups I made with the gun the last time at the range. Since this was 10 shots and not 5 or 7, I have to say that I did measurably better with the new scope.
Since the built-in pressure gauge said there was still about 180 bar left in the pistol after the first group, I loaded the clip with another 10 JSB Jumbo Heavys and shot again. Before shooting, I adjusted the scope through rough guesswork and managed to hit the lower right quarter of the bull at which I was aiming. I really like how well the new UTG scope adjusts, and I like how the knobs can be locked after every adjustment.
This is significant. It means there are more than the 7 shots per fill that I reported in Part 3. But I had to overfill the gun to get the other shots. More on that thought at the end of the report.
Please note that the largest of these 2 groups was 1.053 inches for 10 shots. In the previous test, the 10-shot group fired with the lighter JSB Exact 15.9-grain Jumbos was 2.093 inches. This one is a good four-tenths of an inch smaller. I think that is good evidence that the scope is the big difference this time; and if there’s a secondary difference, it’s that I am learning to shoot this pistol. However, I didn’t shoot this 18.1-grain JSB before, so my comparison isn’t perfect.
The trigger-pull was extremely long and mushy as the pistol came from the box, and it does not help the groups one bit. It’s hard to hold steady when pulling through a long, heavy trigger-pull. Also, I have to hold the end of the scope with my left hand to keep the spacing for my eye so I can see through it. If I were to try to freehand it, I would never be able to see through the scope because the image would keep blacking out with small movements of my eye and hand. So, the hold is both difficult and uncomfortable. A pistol scope would be better, though I doubt the groups would get any smaller with one.
The trigger is adjustable, however, and this is one of those rare instances in which the adjustments really work! I adjusted the long pull in my office after the range and got the trigger breaking fairly crisp and quite a bit lighter. This might have helped the groups by some amount.
I’ve tried adjusting this Quattro trigger in some Hatsan spring rifles before and didn’t see as much improvement; but, of course, in a PCP the trigger isn’t holding such a heavy spring.
Next, I filled the pistol to 3,000 psi and loaded 10 Beeman Kodiaks. This time I thought I had it right until the two final shots. Shots 9 and 10 went high and right from the main group. Eight shots went into 0.701 inches, but the last 2 shots opened the group to 1.118 inches.
This group sort of reminded me that 10 shots were too much for the AT P1 pistol on a 3,000 psi fill, even at 25 yards. Eight seemed to be the maximum with the new UTG scope. But there was one more pellet to try.
I took Skenco New Boy Seniors along, but they’re too long for the Hatsan’s clip. They protrude and don’t allow the clip to turn when the gun is cocked. The only other pellet I had to try was the Crosman Premier.
Once more, I got 8 shots in a smaller group that measured 0.791 inches, then shots 9 and 10 went wide and opened it to 1.266 inches. One went to the left and the other went right, as though I was throwing curve balls. I couldn’t see the pellets in flight; but when I saw the hole each one made, it came as a surprise.
Ten Crosman Premiers went into 1.266 inches at 25 yards from a rest. The first 8 shots went into 0.701 inches, and shots 9 and 10 went wide right and wide left. Once again, 8 shots were relatively close with 2 fliers.
Based on all this data, I’m going to say there are only 8 good shots per fill in this pistol with a 3,000 psi fill. Given the results of both days on the range, I believe I can safely make that statement. But since I was able to fill the pistol to greater pressure and get additional good shots, I think it might respond well to a fill pressure of 3,200 psi and be able to shoot all 10 shots.
The Beeman Kodiaks and Crosman Premiers seem to be the best 2 pellets in this pistol. Next time, I might try a third pellet that hasn’t been tried…like the JSB Exact RS.
Not done yet
I’m not yet finished with the Hatsan AT P1 pistol. In the next test, which I think will be the final one, I’ll try filling to 3,200 psi to see if I can get 10 good shots on one fill. If that doesn’t work, I’ll go back to the 3,000 psi fill and only shoot 8 shots per group. Now that I have a good scope, 2 good pellets, a knowledge of the power curve and fill pressure limits, plus a newly adjusted trigger, I think I can make the gun perform at its best.
Why am I willing to do all this testing? Because there aren’t that many good PCP air pistols available, and I think this might be a good one once I learn all its secrets. I owe you readers that much because so many of you are considering this one.
by Tom Gaylord, a.k.a. B.B. Pelletier
This is the summary report in this series. I’ll give you my thoughts on how this test went, and I expect you to comment, as well.
Three barrels were used in this test. One was the factory barrel that comes with the .22-caliber AirForce Talon SS. It’s a 12-inch Lothar Walther barrel that has a choke of about a half-thousandth inch reduction in the bore diameter for the final 2 inches of length. That makes all the pellets of uniform size as they leave the muzzle, and it may potentially stop any in-bore wobble. This barrel has the standard airgun twist rate of 1-turn-in-16-inches of bore travel, written as 1:16″.
The other 2 barrels were made by Dennis Quackenbush. Neither barrel is choked. One is a 1:12″ twist; the other is a 1:22″ twist. They’re also about 12-inches long and are held in the gun by AirForce Talon SS barrel bushings. Several comments have suggested that because these barrels are different than the Lothar Walther barrel, this test is somehow not fair. But the results of all the shooting prove otherwise. Sure, there are variations from barrel to barrel, depending on the power used and which pellet was shot. But the results are so close between all 3 barrels that whatever differences there might be are overridden by the similarities. In other words, I’m suggesting that if Lothar Walther had made all 3 barrels, there would be similar differences.
The 3 barrels used in the test. Factory barrel in the middle.
I believe the twist rates are what drive the results. We weren’t searching for the most accurate barrel in this test. We were looking for behavior changes as conditions were changed. And we got that.
The first thing that was tested was velocity. Both pellets — the 14.3-grain Crosman Premiers and the 15.9-grain JSB Exact Jumbo were shot from all 3 barrels at each of 3 predetermined power settings. These settings were marked on the gun so they were kept constant throughout the test.
The power settings were the power indicator screw all the way to the left (the lowest setting), and the power screw centered on each mark (settings 6 and 10).
I reviewed the velocity for you in Part 8. Here’s a summary of that report.
In all cases, the velocity increased the most between power setting zero and setting 6. The velocity increase from setting 6 to setting 10 was always smaller than the increase from setting zero to setting 6, and that’s irrespective of the twist rate or which pellet was shot.
What you’re seeing here is the slowing down of the rate of velocity increase as the air flow increases. That’ll become clear in a moment when I discuss the rifle’s maximum velocity potential.
As the twist rate slowed (1:22″ is slower than 1:12″), the velocity increased at most power settings with most pellets. There was one instance with the 1:22″ barrel when the JSB Exact pellet actually went 2 f.p.s. slower at setting 10 than at setting 6; but with all other barrels and pellets, there was always a velocity increase as the power setting went higher.
Focusing on the 1:22″ barrel for a moment, we see that the velocity increases between setting 6 and setting 10 were not as great as they were in either the factory (1:16″) barrel or the 1:12″ barrel. This suggests what we have suspected all along — that the twist rate of the barrel does slow down the pellet as it gets tighter. And we can see from this test that the phenomenon is most apparent at the lower power settings. At the higher power settings, the differences seem to shrink, indicating that the influence of the power setting is overriding the influence of the twist rate. I believe this is an important finding, and it sets up the next observation, which is that the top velocity of the gun was fairly close for all 3 barrels, regardless of the twist rate. The type of pellet made more difference to the top velocity than the barrel twist rate did.
It should be obvious from these results that the Talon SS powerplant has upper limits that cannot be exceeded by forcing more compressed air through the barrel. This illustrates the relationship between barrel length and velocity in a pneumatic airgun.
A second thing I found interesting is that power setting 6 is very close in performance to power setting 10. In the case of the 1:22″ twist barrel, it’s remarkably close…but it’s close for all three barrels. A prudent airgunner might consider this when setting the power wheel adjustment on his Talon SS, knowing that a lower setting uses less air, yet gives velocity that isn’t that much slower.
A third thing is that the velocity performance of the 1:22″ barrel is so good at power setting 6 that it makes power setting 10 useless. Take that thought just a little farther, and you’ll see that all power settings above setting 10 are pretty much a waste of air in a Talon SS with a 12-inch barrel, regardless of which pellet you use.
Next, I tested all 3 barrels with both pellets shot at all 3 power levels at 10 meters (11 yards) and 25 yards. Following that, I tested all 3 barrels and both pellets, again, at 50 yards, only I didn’t use the zero power setting. This was where my eyes were opened regarding the effects of twist rate.
I analyzed the accuracy in 2 different reports. One (Part 9) was the 10-meter and 25-yard accuracy and the other (Part 12) was the 50-yard accuracy, alone. Now, with the table above we can combine these results and analyze all the accuracy data together.
The first observation I’ll make is that at 10 meters, I got 10-shot groups that ranged from as small as 0.092 inches to as large as 0.578 inches. The factory barrel gave the best results with the JSB pellet; but with the Premier, it was the 1:22-inch twist that did the best. Curiously, that pellet and twist rate didn’t seem to change that much as the power was increased (at 10 meters). With all other barrels and pellets, the group size did change a lot as the power changed.
It’s too simple to say the factory barrel with the 1:16-inch twist rate is the best; but of the 3 twist rates in this test, it certainly is the most flexible across the board. However, you’ll notice that the 1:12-inch twist barrel did shoot the best single group (with JSB Exact pellets) at 50 yards. That group is so close to the Crosman Premier group shot by the 1:16-inch barrel that I can’t call a clear winner — BUT — here is what I CAN say. The Quackenbush 1:12-inch twist barrel is certainly capable of shooting 50-yard groups at least as tight as those shot by the Lother Walther barrel; and in my mind, that puts the barrel-equivalency question to rest.
Another observation is that the 1:22-inch twist barrel was just as good at 10 meters as the other 2 barrels, in general, but look at how the groups opened at 50 yards! That says something very strong about the relationship of the twist rate to accuracy. And it also brings up a second observation.
Premier pellets and JSB pellets performed differently throughout this test. Just look at the 50-yard results for Premiers and JSBs with the 1:12-inch twist barrel, and you’ll see what I mean. This is one more bit of evidence that barrels have preferences for certain pellets.
This will be my final remark in this series of reports, and it does not come from the data collected in this test but from the 5-part test of the Diana model 25 smoothbore. In that test, we saw that the smoothbore was able to place 10 JSB Exact RS pellets into a group measuring 0.337 inches at 10 meters. However, at 25 yards, the same pellet loaded the same way made a group that measured 3.168 inches. That difference tells us clearly that spin and not aerodynamic drag is the main key to pellet accuracy. I think we now see that twist rates do matter a lot, and the standard rate is the best all-around rate for now.
At 10 meters, 10 JSB Exact RS pellets made this 0.337-inch group.
At 25 yards, the same JWB-Exact-RS pellets, seated to the same depth, made this 3.168-inch group. They are clearly not accurate after 10 meters.
by Tom Gaylord, a.k.a. B.B. Pelletier
Today, we’ll look at the performance of the Hatsan AT P1 PCP air pistol for accuracy at 25 yards. It took a long time between this test and the last one because this gun is too loud to discharge inside the house. I had to do it for the velocity test and my ears are still ringing. I waited for a day at the range to test the gun for accuracy.
I mounted a vintage Weaver K-856 scope on the gun for this test. It’s a fixed 8x scope with a 56mm objective lens. I thought it would be clear enough at 25 yards (parallax set for 100 yards), but it turned out to be fuzzy. I will change scopes for the next test.
Before I left the house, I filled the gun to 3,000 psi with the Hill pump. You may remember that this pistol has a proprietary Hatsan fill probe, and I wanted to install it on something I could leave it on for a while. My carbon fiber tank is too busy with other guns, so I dedicated the Hill for this job. Because the AT P1 has such a small reservoir, I felt it would be okay to fill the pistol this way. This is the problem with proprietary fill couplings — they have to be installed on something, making it impossible to use that fill device for your other pneumatic guns that have universal Foster fittings.
After filling the gun, I looked at the Hatsan tank gauge. It read about 50 bar, even though I had just put in 206 bar. I knew it was full, so I left it alone. The next morning, the gauge needle was up to 100 bar, but it never did read correctly. That caused a problem at the range when I shot the gun down too far. It was then that I learned that the gauge needle bears no relation to how much air is in the tank.
I started out shooting a group of 5 Crosman Premiers. The first shot landed a quarter-inch below the next 4. The total group size was 0.678 inches, but 4 of those shots went into 0.322 inches. As it turned out, that was the best group of the day.
The trigger-pull was both too long and too heavy for the best in precision. I can normally work around almost anything, but this time the trigger-pull was a real hinderance to good shooting.
I shot the next 5 Premiers at a fresh target after adjusting the scope down. This time, 5 shots went into 0.993 inches, which is considerably larger than the first group. It alerted me to the fact that there may not be 10 good shots on a charge of air.
The pressure gauge on the gun now reads about 180 bar, so I thought there were another 10 good shots in the gun. It wasn’t until later that I discovered the gauge doesn’t read the pressure correctly.
The next 10 shots were JSB Exact 15.9-grain Jumbos. They landed in a group measuring 2.093 inches between centers. That certainly isn’t a good group — especially for just 25 yards. This group has too many shots and was shot with too little air pressure in the tank, but even then the shots are so scattered that I doubt it’s the right pellet for this pistol. But because I don’t know that for sure, I’ll try this pellet again in the next test.
I filled the tank again and changed to Beeman Kodiaks. This time, 10 pellets went into a group measuring 1.464 inches. The last shot went far to the left of the main group. Because it landed in the white, I was able to see it hit the paper. That was the tip-off that 10 shots were too many — even at only 25 yards.
I’d wanted to shoot 10-shot groups, but the AT P1 doesn’t seem to have enough air for 10 good shots on a single charge. According to the chronograph testing I did on Part 2, it has air for about 7 shots, so I limited the next groups to that.
The learning curve this day was too steep for me to be satisfied with these results. I’d lost my edge toward the end of the session, and it wasn’t worth pushing on. I’ll return for a second try at 25 yards with different pellets. And I’ll give those JSB Jumbos a second chance. If I can’t do a lot better than this, I won’t bother trying to shoot the pistol at 50 yards.
The trigger-pull on the AT P1 pistol is too long and heavy for the best accuracy. Also, the scope needs to be changed to give the pistol its best chance to do well. Hopefully, I’ll be able to find another good pellet next time and these problems will disappear. As powerful as this air pistol is, it’ll make a good hunting airgun if it can hit what it shoots at.
by Tom Gaylord, a.k.a. B.B. Pelletier
Today, I’ll report on the final test in this series. This isn’t the final report — just the final test, which is the barrel with the 1:12″ twist, shooting at 50 yards. Get ready to be surprised. I know I was!
I did this test on the same perfect day as the factory barrel that was reported last week in Part 10, and the weather was perfect most of the time. From time to time, there was a very slight breeze that I waited out before shooting. The shooting conditions were as good as they get.
I used the same two pellets we’ve been shooting all along, and they were shot at power settings 6 and 10…just like the other 2 barrels that went before. The gun was shot while resting on a sandbag that’s very stable. When the tank was filled or the power was changed, I always shot one shot to settle the valve. Experience tells me that’s all that’s needed.
The tank was filled to 3,000 psi.
Power setting 10
I first shot both pellets on power setting 10. And 14.3-grain Crosman Premiers were hitting low and to the left. One of them only nicked the target paper, so I photographed the target before taking it off the backer paper, so you could see the complete group.
Here are the two 10-shot groups of Premiers. Notice that they’re hitting to the right of the aim point, which is the center of the bull they touch. The group shot on power setting 10 is at the top, and it shows why I like to use backer paper when shooting at 50 yards.
Then it was time to test the 15.9-grain JSB Exact Jumbo 15.9-grain pellet on power setting 10. This is where the surprise comes! Ten pellets made a 1.259-inch group! If you check back with the results the factory barrel gave, you’ll see that this group is very close to the best group made by the factory barrel (1.153″ for 10 shots with the same JSB pellet on power setting 6), and it’s equal to the group that was shot on power setting 10 (1.283″). This addresses a question many of have had from the beginning of this test — namely, are the Quackenbush barrels equal to the Lothar Walther barrel?
With so little data, it’s impossible to say if these two barrels are exactly as good, but what we now can say is that one of the Quackenbush barrels gave some groups that are at least equivalent to those from the factory barrel. The difference is so small that it might be due to the twist rate rather than the quality of the barrels. That was the position I took at the start of the test, and I think this demonstrates it was valid.
Power setting 6
Next, it was time to test the 1:12″ barrel on power setting 6. Ten Premiers went into 2.234 inches, which is only slightly smaller than the same pellet on power setting 10. As before, the pellet stuck the target low and to the right.
It’s official — the 1:12″ barrel does not like Crosman Premiers out at 50 yards. But that wasn’t the only pellet in this test.
With JSB Exact Jumbo 15.9-grain domes, the barrel did nearly as good on power setting 6 as it did on setting 10. Ten pellets made a 1.363-inch group. Like the Premiers, the JSBs also performed about the same on setting 6 as on setting 10. But that’s not the real lesson. The real thing to note is that the 1:12″ twist barrel was not as good at 25 yards as the factory barrel, yet at 50 yards it almost caught up. In other words, the accuracy of the factory barrel degraded faster as the distance increased than the barrel with the faster twist.
What has been learned?
This is not the final report. I’ll add these results to the previous summary report given in Part 9, and we’ll be able to see all 3 barrels at all 3 distances with both pellets at all 3 power levels. But if I had to give a quick analysis, I’d say the 1:12″ twist barrel surprised me at 50 yards by being better than I expected. At least it was better with the JSB pellets.
And that fact alone — that a barrel can be so much better with one pellet than with another — is good to know. This test has demonstrated that principle beyond all doubt.
A lot more testing needs to be done to thoroughly see all the relationships, but I’ll tell you what I know in the next report, which will be the final report for this series. I think we can advance our knowledge of how pellets perform by quite a bit by combining the results of this lengthy test, the smoothbore test and the pellet velocity versus accuracy test. We’ve been exploring this theme for nearly 2 full years now, and I think we’ve learned a lot!