Posts Tagged ‘Crosman Premier pellets’
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!
by Tom Gaylord, a.k.a. B.B. Pelletier
Continuing our look at the 3 different twist-rates, today I’ll shoot the factory Lothar Walther barrel at 50 yards. The factory barrel has a 1:16″ twist rate that has become ubiquitous for airguns and is the very thing this test is designed to examine. Last time we looked at how the 1:22″ twist barrel did at 50 yards, with 2 different pellets fired at power levels 6 and 10. Today, we’ll see the same thing with the factory barrel.
This test was performed yesterday, and the range conditions were perfect. There wasn’t a breath of air to be felt for most of the shooting session, and only an occasional puff of air later on in the morning after I swapped barrels for the final test. I’ll report on that set of results in the next report. Today is devoted to the factory barrel.
The AirForce Talon SS shoots with a fill of 3,000 psi, so before the test I filled the reservoir. Twenty shots would be fired at power setting 10 and another 20 at power setting 6, plus one shot at the start of the test and when the power wheel was changed. I haven’t reported that fact until now, but it’s my standard practice when shooting at 50 yards with a Talon SS.
Valve needs to be exercised
I have learned that the Talon SS valve needs to be fired one time following power adjustments to get it set at the new power level. The first shot will usually be like the gun was on the previous power setting, but the second shot will be solidly at the new setting; so I always take one shot to set the valve with every fill and at every power change.
Shooting off the bench at 50 yards on a perfect day with the Talon SS was enjoyable.
Power setting 10
I started with power setting 10; so when it was time to shoot on power setting 6, the reservoir would have less than the full fill pressure. That way, I knew the gun would be right in the middle of the power curve.
The first pellets I tested were 14.3-grain Crosman Premiers. Because the groups had dropped so far below the aim point in the previous test with the 1:22″ barrel, I dialed up the elevation several clicks for this test. I was hoping to hit the bullseye with the new sight setting, but Premiers on power setting 10 still dropped about 3.50 inches at 50 yards. Ten Crosman Premiers went into a group measuring 1.567 inches between centers. While that’s on the large side for a Talon SS in my experience, it was still a very round group.
At 50 yards, 10 Crosman Premiers went into this round group, which measures 1.567 inches between centers when the power was set to 10.
JSB Exact Jumbo
Next, I switched pellets to 15.9-grain JSB Exact Jumbo and shot another group of 10. This was also at power setting 10, so the gun’s valve did not need to be awakened. These pellets hit about 2.50 inches below the aim point, so they landed higher than Premiers at the same sight setting. This time, the 10 pellets went into 1.283 inches — a much better group than the Premiers, though there was a hint of vertical elongation to this group.
Ten JSB Exact Jumbo pellets made this 1.283-inch group at 50 yards on power setting 10. This group is slightly vertical.
The difference between the Premier group and the JSB group was evident through the scope without walking down to the target. Clearly this barrel likes the JSB pellet better. What did surprise me was that even on this perfect day I did not shoot a group smaller than one inch. I’ve done that so many times in the past that I sort of expected it — especially on such a perfect day. Well, it just demonstrates the difficulty of shooting such tight 10-shot groups at this distance.
Now, I cranked the power wheel down to 6 and shot both pellets, again. The first shot settled the valve at this new setting, then the groups began in earnest. JSBs went first since I’d just finished shooting them at power setting 10.
This time, 10 JSB pellets went into a group that measured 1.53 inches between centers. It was larger than the same pellets on power setting 10, but smaller than the Premiers on setting 10. The group is fairly round, though most of the shots are clustered on the right side.
Ten JSB Exact Jumbo pellets made this 1.53-inch group at 50 yards on power setting 6. Notice that 7 of the 10 pellets landed on the right side of the group.
The final group was 10 Premiers fired on power setting 6. They made a group measuring 1.261 inches, which is the best group of the 4 shot with this barrel. It’s more open than the best group of JSB pellets, but the overall measurement places it at the top of the ladder.
Did you notice that the pellets crossed in their performance relative to power, with JSBs doing best on power setting 10, while Premiers did best on power setting 6? I wouldn’t make too much of that because we don’t have enough data to make any conclusions, but it is interesting. In the macro, it does appear that Premiers prefer lower power while JSBs prefer higher power — at least at 50 yards.
I have to admit that I was surprised not to see even one group that measured less than one inch. I’ve shot so many small groups with this rifle that I expected it this time, at least with one of the four groups that were produced.
In the next report, which is the same shooting done with the 1:12″ twist, there will be a surprising result. So, there’s still more to come.
by Tom Gaylord, a.k.a. B.B. Pelletier
Today, we’ll begin looking at the effects of the rifling twist rate on the accuracy of our test AirForce Talon SS rifle in .22 caliber at 50 yards. If you’re prone to jumping to conclusions before all the data is in, I have to caution you that today’s test will look bad because I’m testing the custom barrel that has the 1:22″ rifling twist. We know from the earlier tests that this barrel was most accurate at 10 meters on power levels zero and 6. Above that power level and also out at 25 yards, the accuracy of this twist rate broke down. So, it would be reasonable to assume that this barrel will give results that are even worse at 50 yards.
That didn’t stop me from trying my hardest to shoot well. I was able to watch each pellet go into the target paper because of the distance, and that was disconcerting when the pellets landed so far from the aim point and from each other. Let’s take a look at how the rifle did.
The day was nearly perfect, as it has to be to get good accuracy from pellets at 50 yards. The air was calm, except for some light breezes from time to time. I was able to work around these breezes and get the results I was after.
I decided not to test the rifle on zero power because of the long distance to the target. Any breeze would have so much time to blow the pellets off course that I felt it wouldn’t prove anything. So, both pellets were shot on power levels 6 and 10. That’s how I’ll test all 3 barrels.
You may remember that this barrel produced velocities that were very close to each other at power levels 6 and 10. With 14.3-grain Crosman Premiers, the respective velocities were 840/854 f.p.s.; and with 15.9-grain JSB Exact Jumbos, the velocities were 817/815 f.p.s. We expect the pellets in this test to go to the same place on the target, and I would expect the two groups for each pellet to be pretty similar in size.
I started with Crosman Premiers and the power set to 10. I did not adjust the scope since completing the 25-yard accuracy test and the center of the group landed about 3.9 inches below the aim point. Ten pellets went into a group that measures 2.04 inches between centers.
Ten Crosman Premiers went into 2.04 inches at 50 yards on power setting 10. The center of this group was about 3.90 inches below the aim point with the scope set for 25 yards. The pellet at the top center is part of another group — not this one. I did account for the full size of the pellet on the left that just clipped the edge of the target paper.
On power setting 6, the center of the group also struck the target 3.90 inches below the aim point. These measurements of the groups are just approximate since the center of each group was difficult to locate precisely. The 10-shot group size on power setting 6 was 2.607 inches between centers. This is slightly larger than the group shot on power setting 10.
JSB Exact Jumbo
Next, it was time to test the JSB Exact Jumbo pellet. I started with power setting 10. The center of the group landed about 4.25 inches below the aim point.
Ten pellets shot on power setting 10 went into a group that measures 2.509 inches between centers. The group is much taller than it is wide.
On power setting 6, the 10-shot group size was 3.222 inches between centers. This group is considerably wider than the group shot on setting 10. Why that is, I have no idea.
As expected, neither pellet did especially well at 50 yards with the 1:22″ twist barrel. They did stay closer together than I expected, however.
The Premiers were more accurate than the JSBs, which parallels what both pellets did at 25 yards.
I don’t see any real evidence of tumbling pellets with either pellet on either power setting, so it’s too simple to say they’re just destabilizing. They’re less accurate but still stable at this distance. There’s probably something profound in that — something like the pellets still fly point-forward, but erratically. I can’t prove anything, yet, but now I have one barrel’s results in the can and it’s time to look at the factory barrel next. And that one has the twist rate that the manufacturer thinks is best for this airgun.
When I pitched the idea for this test as a feature article for Shotgun News, the editor told me he has never seen a test like this before. Neither have I. This may, in fact, be the first time anyone has published the results of testing three rifled barrels of different twist rates in the same gun under the same conditions. It probably has applications in the firearms world as well as for airguns. So, you readers may be in on something that’s being done for the first time.
We still have to test the factory barrel and the 1:12″ twist barrel at 50 yards. As a final report, I’ll summarize the entire test and the lessons I believe it teaches us.
by Tom Gaylord, a.k.a. B.B. Pelletier
Today, I was all set to report the velocity of the .22-caliber Hatsan AT P1 PCP air pistol, when I discovered that there’s more I need to know about this airgun. I’d like to thank those who’ve been waiting patiently for this second report. I stalled for a long time because Hatsan uses a proprietary quick-fill probe. That means I have to undo one of my more universal fill connectors to attach their probe. Thankfully, the threads on their probe are standard 1/8″ BSPP that connect to most air hoses coming from tanks and hand pumps these days (I can still remember when that wasn’t true!), but I was working on both the Condor SS and the twist-rate report and needed a fill device for both of those. In the end, I pressed my Hill pump into service, and it proved to be a great way to fill the AT P1 pistol.
The first problem I encountered was with the 10-shot rotary clip — but I want to stress that it wasn’t the pistol’s fault. It was mine. I tried loading 28.4-grain Eun Jin domes that looked like they fit the clip well, but proved to be too long and jammed the gun.
Because they were the first pellet I tried, I thought the gun might be broken until it dawned on me that the pellets were the problem. Once I changed to Crosman Premiers, the gun functioned perfectly and there were no more cocking or feeding problems.
Rotary clips are sensitive to the length of pellets. If they stick out on either side of the clip, that can cause the gun to jam, as this Hatsan did. So, when selecting pellets for a rotary clip, keep this in mind. I chose the Eun Jin pellet for the weight. I thought it would allow this powerful pistol to develop its maximum power, but I went too far.
Removable air reservoir
In Part 1, I completely neglected to mention this pistol has a removable air reservoir. I saw the degassing tool in the tool kit and knew that it could only be used on the other (hidden) end of the reservoir, but for some reason I didn’t think to mention it.
Of course, the reason for a removable tank is so you can carry extra charged tanks in the field. Each one will give you more shots. I don’t think this is such a great feature after you learn how many shots you can get on a fill, but the choice is yours. At least Hatsan gives you the option.
Shots per fill
This will be the remainder of the report because I discovered during velocity testing that the AT P1 pistol has a very specific power curve. It’s not an inverted bathtub curve — where the velocity rises to the optimum level and remains there for a number of shots before falling back down again. Instead, the velocity rises, peaks and drops instantly. The curve looks like a peaked mountain with no flat spot at the top.
The manual says to fill to 3,000 psi and that there are 35 useful shots per fill. Several readers expressed doubts that the 50cc reservoir held enough air to give 35 powerful shots, and I agreed with them. If this was a target pistol, then 35 shots would be very possible; but at the power Hatsan claims, which is a .22-caliber pellet traveling 780 f.p.s. at the muzzle, it seems impossible to get 35 good shots on so little air. And, indeed, it isn’t.
My first fill was higher than 3,000 psi, and the velocity was depressed for many shots. When it did rise, it did so in a straight up and straight down fashion. There was no group of shots going at similar velocities. This told me I needed to control the fill very carefully.
I also noticed that the pistol fell off the power curve with about 1,800 psi remaining in the reservoir. But I didn’t stop shooting there. I stopped with about 1,500 psi remaining in the reservoir. From this test, I was able to determine that the pistol used about 62.5 psi per shot. I did that with a chronograph and with an accurate pressure gauge on the hand pump. The pressure gauge that’s built into the test pistol’s reservoir reads several hundred psi too low to be of much use.
I know how much air is in the reservoir when I start shooting because that’s what the pump’s gauge reads when I stop filling. I know how much air is in the reservoir when I stop shooting because that’s the spot on the gauge where the reservoir inlet valve is overcome by pressure during the next fill — you can see this when the gauge needle clicks at the opening of the inlet valve.
It took 1.5 pump strokes per shot, so refilling the reservoir went very quick. That’s why I believe the Hill pump is the best way to go, and the possibility of spare reservoirs isn’t worth the effort.
The shot count test
The next test I conducted began with a fill to exactly 3,000 psi on the hand pump’s pressure gauge. I used Crosman Premier pellets, exclusively for this test. I’ll give you the velocity readings and then interpret them afterward.
I’m not going to give you an average for this string because I don’t know which shots you want to consider as the good shots. Clearly, the pistol was slower at 3,000 psi on the hand pump gauge. And, remember, this is with the more accurate hand-pump gauge. The pistol’s built-in gauge was still showing about 2,700 psi at this point. Either way, there’s too much air pressure in the gun because the valve isn’t opening as long as it should, as evidenced by lower velocities.
Let’s say I like 761 f.p.s. for the first shot. If you agree, then the first 5 shots in this string were wasted. At 62.5 psi per shot, the gun was overfilled by 312.5 psi when it was filled to 3,000 psi. Since these gauges don’t read that accurately, let’s round that back to 300 psi overfill and say I need to stop filling the reservoir when the pressure gauge reads 2,700 psi.
If you select a different velocity as the start point of the shot string, then the beginning fill pressure will need to be adjusted accordingly. This is why I am not giving you an average velocity today. I can give average velocities, but before I do you need to know what is behind my numbers, because this pistol operates within narrow limits.
If I take the second reading of 761 f.p.s. as the ending shot in the string, there are a total of 7 good shots in the string. I think that’s probably too restrictive, and I need to expand my velocity variation allowance. If I allow a velocity variation of 74 f.p.s. between the fastest and slowest shots in the string, I can get 16 good shots on a fill and can start the fill at exactly 3,000 psi.
Do you see how I’m doing that? I’m using the chronograph numbers and accepting all shots until the pistol no longer drives Crosman Premiers out the muzzle at a velocity of greater than 700 f.p.s. My choices are arbitrary; but until I make them, I can say nothing about the shot count of this pistol
Well, maybe that’s not entirely true. Whatever I select as the acceptable velocity variation, I can say with certainty that this air pistol can never get 35 useful shots on a single fill. Where I draw the line is my choice, of course. If I want to shoot groups at 50 yards, the variation has to be tighter than if I want to hunt with the pistol out to 30 yards. Do you see how the anticipated use of the gun drives the useful number of shots you’re going to get?
When you change the clip, the gun must be cocked to pull the loading probe back out of the clip. Then, the clip’s axle must also be withdrawn to the front of the gun and held out of the way. That’s a separate brass bolt on the right side of the gun. The clips come out and go back in easily enough when these things are done.
Here you see the bolt probe that pushes the pellet into the barrel (brass pin in the clip recess) and the brass clip axle (the head is a brass knob) that’s been withdrawn to the front of the gun to remove the clip.
This gun is LOUD! I had to wear electronic ear protectors when testing it in my office. And although my office door was closed, my wife, Edith, remarked on the loud discharge when I was finished.
In the next report, I’ll test the pistol with several good pellets and give you some of the velocity data you’re used to seeing. But when I do, you’ll know what’s behind my numbers.
by Tom Gaylord, a.k.a. B.B. Pelletier
Before we begin, there was a request last week for me to test the Benjamin 392. I thought I’d tested it already, and it turns out I did. Click see all 5 parts on the old blog.
The question of barrel equivalency
Today, we’ll look at the accuracy side of this test, where yesterday we looked at how the twist rate affects velocity. Before I begin, however, we have to settle an issue that’s in a lot of people’s minds. Namely, is it reasonable to test barrels made by Dennis Quackenbush against a Lothar Walther factory AirForce barrel? Will the test results be skewed for that reason and not because of the different rifling twist rates? Or will the twist rates determine part of the results and the barrel’s pedigree determine the rest?
To carry that kind of logic out to its conclusion, every barrel will be different. Who’s to say that one Lothar Walther barrel is not better or worse than another? The fact is that we know that some of them will stand apart — being either better or worse than the norm. There’s no way to test the exact same barrel with all 3 twist rates because we cannot adjust the twist rate of a rifled barrel. Once it’s built, it is whatever it is. Three separate barrels have to be used for this test, whether they’re made by Lothar Walther or by someone else.
Another thing to consider is that other smallbore barrels made by Dennis Quackenbush in the past have proven to be as accurate as barrels made by Lothar Walther. I’m now talking about barrels of the same caliber — not comparing .22-caliber Walther barrels against .308-caliber Quackenbush barrels. I know of .22-caliber barrels and .25-caliber barrels made by Quackenbush that can go against the best barrels made by Lothar Walther.
But in the end, we can never know if the barrels I’m using for this test are exactly as accurate as the Lothar Walther factory barrel I am also using. There is just no way to know that. There is, however, a way of getting pretty close. If the Quackenbush barrels produce some groups in the same accuracy range as the Lothar Walther barrel, then we can be assured that we are testing barrels of similar quality. We can never be entirely certain they are exactly as good, so this is as close as it is possible to come. And, by the same logic, that is all we could do if Lothar Walther had made all 3 barrels used in this test.
Lothar Walther is not going to make test barrels for a test like this unless they want to. There is no way to contract with them to make one-off barrels that have the different twist rates we are testing. They don’t make one-off barrels — at least not for the public. There are barrel makers who do make one-off barrels, and Dennis Quackenbush is one of them. We’re going to have to be satisfied with the barrels he has provided and look at the results to see if we believe his barrels are as good as the factory barrel we’re testing.
On with the test
With that issue set aside, let’s look at what the 3 barrels did in this test.
The group sizes in the table are shown in inches.
The first thing I looked at was the results of the 2 Quackenbush barrels against the factory Lothar Walther barrel, and I learned something interesting. At 10 meters, the 1:22″ twist barrel shot better than the factory barrel with Crosman Premier pellets — not by a little, but by a significant margin. On both zero and 6 power, the 1:22″ barrel made groups that were one-tenth of an inch smaller than those made by the factory barrel. On power setting 10, the factory barrel beat the 1:22″ barrel by only four one-hundredths of an inch. I think that’s significant. It shows that the 1:22″ twist barrel can keep up with and even exceed the Lothar Walther barrel…at least to 10 meters.
The 1:12″ twist barrel wasn’t quite as good as the factory barrel at 10 meters, but it was very close. At power settings zero and 6 they differed by just a few thousandths of an inch. On setting 10, the factory barrel exceeded the 1:12″ barrel by the same four one-hundredths of an inch that it did with the 1:22″ barrel.
These results tell me that the two barrels made by Dennis Quackenbush are as capable of making good groups as the Lothar Walther barrel. The differences in the group sizes are less than the measurement errors made when measuring the groups. That puts the barrel equivalency question to rest in my mind. I’m willing to accept that the results of this test are from the different twist rates and not from the inherent quality or lack of quality of the barrels being tested.
Ten meters is really too close for definitive results when the question of accuracy is on the line. That’s why the test was also shot at 25 yards, and later I’ll shoot it at 50 yards. It was at that distance that the factory barrel really shined. With 14.3-grain Crosman Premiers, the factory barrel was more accurate on power setting 10 than on the lower settings. With 15.9-grain JSB Exacts, the factory barrel did its best on power setting 6. But both of the other barrels did not perform their best at this range.
The 1:12″ barrel shot Crosman Premiers best on power setting 6, but it shot JSB Exacts about the same on settings 6 and 10. There was a little difference with the Exacts, but it was down in the measurement error margin.
The 1:22″ barrel, on the other hand, got worse with Premiers as the power was increased. And the difference between the best and worst groups was large enough to be more than a coincidence. It was almost twice as large on power setting 10 as it was on power setting zero (1.082″ compared to 0.671″).
With JSB Exact pellets, that trend was reversed. The greater the power, the smaller the groups became. For both pellets at 25 yards, the 1:22″ barrel was not anywhere near the factory barrel at the same distance. Only at power setting zero with Premiers was that barrel close to the factory barrel, and the difference was still outside the measuring-error margin.
The 1:12″ barrel performed similar to the 1:22″ barrel at 25 yards. Only once, at power setting 6 with Premier pellets, did the 1:12″ barrel exceed the factory 1:16″ barrel.
If you look at the results of the 1:22″ barrel, you’ll note that it falls apart at 25 yards. It held its own at 10 meters; but at 25 yards, it falls far behind the factory barrel.
The 1:12″ barrel does the same, but it doesn’t open up as much as the 1:22″ barrel. There are individual instances where one of the two Quackenbush barrels exceeds the other; but in general, what I’m saying holds true. The factory barrel, however, doesn’t work that way.
The factory barrel holds together at 25 yards, just as it does at 10 meters. Again, there’s a single instance at 25 yards where it is beaten by the 1:12″ barrel (power setting 6 with Premier pellets), but that stands out as the only time the factory barrel was beaten at 25 yards. We can say in this test the factory 1:16″ twist barrel outperformed the other two barrels at 25 yards. That allows me to say two things.
First, I predict that the factory barrel will be the most accurate at 50 yards. Second, I believe that the 1:16″ twist rate is the best twist rate of the 3 we’ve tested.
Don’t get too excited
This test has been too small to say anything with certainty. I said that before we began, and I’m saying it again now. All these results can do is suggest things that should be looked at more closely. Other pellets will give different results — I’m sure of that. And more testing will refine these numbers. Where there’s gross separation between the Quackenbush barrels and the factory barrel, I feel certain the trend will continue with more testing. But where things are close, there might be a reversal of the outcome. There simply isn’t enough test data to say otherwise.
Conclusions so far
Based on the data we see thus far, I think that the 1:16″ twist rate seems to be the best of the three twist rates we’ve tested. At 10 meters, the factory barrel shot 3 of the best 6 results. At 25 yards the factory barrel shot 5 of 6 groups better than the other 2 barrels. Out of the total of 12 results, the factory barrel was the best 8 times. So, 67 percent of the best groups in this test were shot by the factory barrel.
The factory barrel is the best overall barrel in this test so far, and it gets better the farther the distance is to the target.
Because the other 2 barrels beat the factory barrel one-third of the time, I think the question of their quality can be laid to rest. Clearly, they’re giving the Lothar Walther factory barrel a run for the money.
Power versus accuracy
In Part 8, I talked about not needing to use power setting 10 with the 1:22″ barrel if it proved to be accurate enough. The velocity at power setting 6 was so high that I said I could stop there and conserve air. I think I’ve now shown that it isn’t accurate enough. Yes…when you look only at that barrel’s accuracy, you could surmise that it’s accurate enough at power setting 6 to stop at that point. But when the factory barrel is brought into the equation, the 1:22″ barrel falls behind.
Next, I’ll shoot all 3 barrels at 50 yards. I’m planning to shoot only power settings 6 and 10 with each barrel because of the distance involved. This will be outdoors, and the pellets will really scatter in the light breezes if they’re shot on the lowest setting. I will have to wait for ideal range conditions, so it may be quite a while before I’m able to make my next report.