Crosman MAR 177: Part 3

by Tom Gaylord
Writing as B.B. Pelletier

Crosman MAR
The MAR177 from Crosman.

Part 1
Part 2

History of airguns

This report covers:

  • Baseline with Hobbys
  • Today’s test
  • What is the average?
  • Second page of numbers
  • What does “estimate 601” on page 2 mean?
  • But — what is the average velocity?
  • Photos
  • Pressure gauge and fill pressure
  • Big lesson
  • Balanced valve
  • How do I know the ending air pressure?
  • Air Arms Falcons
  • RWS R10 Match Pistol
  • H&N Finale Match Light
  • Loading problems
  • Loudness
  • Summary

Today I test the velocity of the MAR177 I’m reviewing, and I have a baseline from the 2012 test I did, with which to compare it. Some of you asked me what velocity to expect. Well, it is all in the 6-part review I did on the first MAR177. Look at Part 3 of that series for the velocity test. 

Baseline with Hobbys

In that 2012 test I got an average of 609 f.p.s. from RWS Hobbys and the velocity varied by 32 f.p.s. The low was 593 f.p.s. and the high was 625 f.p.s. I got a shot count of 124 shots on one fill.

Today’s test

Today I shot 160 Hobbys on a fill. The fill pressure ranged from a high of 3200 psi to a low of about 2200 psi — according to my accurate carbon fiber tank gauge. Those starting and ending pressures are well above the pressure range of the first gun (which was 2900 psi to 1600 psi). read more


Testing the effect of barrel length on a precharged rifle

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.

Conduct
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.

Because I’m testing with a Talon SS, the air reservoir I’m using is the standard air tank that’s found on both the Talon SS rifle and the Talon that is the lowest-priced model of the line.

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.

Talon barrel test

Analysis
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.

Summary
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.


How does rifling twist rate affect velocity and/or accuracy? Part 13

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
Part 8
Part 9
Part 10
Part 11
Part 12

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.

The barrels
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.

Talon SS precharged air rifle twist rate test 3 barrels
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.

Velocity
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.

Talon SS power settings
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).

 

07-24-13-01-Velocity-table

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.

Accuracy testing
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.

Accuracy table final

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.

Final observation
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 read more


How does rifling twist rate affect velocity and/or accuracy: Part 12

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
Part 8
Part 9
Part 10
Part 11

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.

AirForce Talon SS changing barrels Changing barrels took 5 minutes. The silver barrel has the 1:12″ twist.

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.

AirForce Talon SS filling the tankThe 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.

AirForce Talon SS Premier group still on target stand 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.

AirForce Talon SS Premier group 50 yards power 10 Premiers on power setting 10 gave this 2.577-inch group. See the nick on the right edge of the target paper? I had to guess a little for this measurement, but it isn’t too far off.

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?

AirForce Talon JSB Jumbo group 50 yards power 10 JSB Jumbo 15.9-grain domes on power setting 10 gave this 1.259-inch group. This shows that the 1:12″ barrel can be accurate at 50 yards. read more



How does rifling twist rate affect velocity and/or accuracy? Part 10

by Tom Gaylord, a.k.a. B.B. Pelletier

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
Part 8
Part 9

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.

Crosman Premiers
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.

Talon SS rifle Premiers 50 yards power 10
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.

Talon SS rifle Premiers 50 yards power 6
Ten Crosman Premiers went into 2.607 inches at 50 yards on power setting 6. The pellet hole at the lower right is not part of this group.

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.

Talon SS rifle JSB Heavys 50 yards power 10
Ten JSB Exact Jumbo pellets went into 2.509 inches at 50 yards on power setting 10. The group is taller than it is wide for reasons unknown. read more


How does rifling twist rate affect velocity and/or accuracy? Part 9

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.

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7
Part 8

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.

Rifling twist rate and accuracyThe group sizes in the table are shown in inches.

General observations
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.

What’s next?
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.