Posts Tagged ‘AirForce Talon SS’
by Tom Gaylord, a.k.a. B.B. Pelletier
This is going to be a long report. How long, I can’t say at this time because I’m sure I don’t know everything we’re going to do. Many airgunners have wondered openly how the twist rate of the rifling affects how their guns shoot. But wonder is as far as it’s gone because I’m not aware of any test report that’s ever been written on this subject. Indeed, whenever we get on the subject of twist rates, the equations start flying and we all lean back in our easy chairs while we ponder the implications. But nobody ever seems to do anything concrete to answer the question. That ends today.
What is twist rate and what does it do?
First, let’s all understand what we’re talking about. As a pellet travels down the barrel of an airgun, it’s held by ridges called lands that run along the inside of the barrel. These lands stick up in the barrel and twist in a spiral, engraving the sides of the soft lead pellet and making it spiral as it moves forward. The twist rate is how far the pellet must travel in the bore to make one revolution. A 1-in-10-inch twist rate means that the pellet is turning one complete revolution for each 10 inches of barrel it traverses. That twist rate is written as a ratio — 1:10 inches.
Spinning helps stabilize a pellet in flight. Just as a bullet is made stable by spinning on its axis like a top, a pellet is also stabilized the same way. But pellets of the diabolo design (hollow tail and wasp waist) are also stabilized by the high drag of their tails and the forward weight bias of their design (i.e., more weight in the head than the tail). So, spin is just one of the things that helps stabilize a diabolo pellet in flight, and exactly how much spin it takes is the question we’re discussing. We also want to know what the other effects of the spin rate might be. For instance, does a faster spin slow down the pellet because of greater friction while it’s inside the barrel?
The most common twist rate
When pellet guns were first rifled, they were given the twist rate that was common for the .22 long rifle cartridge at that time, which is one complete turn in 16 inches of travel in the barrel (written as 1:16″). If there was any experimentation with other rates, nothing’s been written about it; so, the pellet gun twist rate has been 1:16″ since the beginning — about 1905. That holds true for all four smallbore calibers (.177, .20, .22 and .25).
I can’t say for certain if other twist rates have ever been used. I hear reports of other rates, such as 1:14 inches, but no proof is ever offered. My thought is that perhaps these other rates are obtained from people incorrectly measuring the twist rate. The simplest way of measuring the twist rate in any rifled gun is to make a mark on a cleaning rod, then pass a wire brush down the bore of the gun on the end of that rod and note how far it goes before the rod makes one complete turn. This method is makeshift, to be sure, but it’s accurate enough for a rough estimate.
I don’t doubt that other twist rates have been used at times, but the makers of those barrels have not made a point of mentioning it in their promotional literature. Twist rate is something airgun writers have elected to ignore over the years, perhaps not finding the subject worth discussion since all airguns seem to have the same rate.
A few of us, though, have wondered what might happen if the twist rate was changed. Since the only way to tell is to test barrels with different twist rates in the same gun, and since nobody makes barrels of different twist rate for airguns, the question has remained unexplored until now. Some time ago, airgun maker Dennis Quackenbush approached me and asked if I would be interested in conducting such a test. I said yes, and we both settled on the Talon SS from AirForce Airguns as the ideal testbed because the barrels can be exchanged so easily.
Dennis made two barrels for my Talon SS. Both are .22 caliber, which is also the caliber of the factory Lothar Walther barrel in my gun. He made these barrels from scratch. They’re cut-rifled, which means that each groove is individually cut. Doing it that way, he was able to use a sine bar (a tool used to measure angles) to control the rifling pitch that results in the twist rate.
One barrel he made had a 1:22″ twist rate. That happens to be the twist rate of the .22 short cartridge when a rifle is chambered for that cartridge, alone. The .22 short bullet weighs 29 grains, nominally. If the rifle is chambered for long rifle cartridges, as well, then the 1:16″ twist is used because the longer, heavier 40-grain bullet requires a faster spin.
In the other barrel, he put a 1:12″ twist. That was for no reason other than it’s far enough from 1:16″ and 1:22″ twist rates that there ought to be some differences that can be observed. One curious sidenote to this test is the fact that Aguila makes a special subsonic .22 long rifle cartridge that has a 60-grain bullet. To stabilize that bullet that leaves the muzzle at around 900 f.p.s., a rifle has to have a 1:10″ twist rate. There are special barrels made for the Ruger 10/22 rifle for just that round. Like the Talon SS, the 10/22 has a barrel that’s quick and easy to change.
The most common method of rifling barrels these days is button rifling, in which a hardened “button” is either pushed or pulled through the bore, cutting all the grooves at the same time (actually, it doesn’t cut the metal so much as it “irons” the steel into the desired shape). The button must be made for a single twist rate, taking into account the thickness of the barrel walls and the type of steel in the barrel because the steel springs back a little after the button has passed through. So, the spring rate of the barrel steel must be controlled by the size and shape of the button, as well as the type and thickness of barrel steel, itself. Using a button is a very fast way to rifle many barrels, but it limits you to just one twist rate per button.
Cut rifling is therefore a slower process but does give the barrel maker more flexibility over the type of barrel he makes. Dennis didn’t put a choke into his barrels because we aren’t interested in their ultimate accuracy. But the factory Lothar Walther barrel is choked. So, this will not be a test that pits the accuracy of the Quackenbush barrels against the Lothar Walther barrel. We’ll be examining accuracy potential, but only so far as one twist rate seems to have an advantage over the other with a given pellet at the same power setting. If something interesting pops up, we may wish to explore it further with other barrels in the future.
AirForce helped, too
Dennis contacted John McCaslin of AirForce Airguns for some of the critical dimensions of the barrels. John shared these with him and also provided the bushings for the barrels he made. Even though they were made 12 years after my SS was made, these bushings fit my rifle perfectly.
Test objective 1
The first test objective is to determine the effect of a different rifling twist rate on the accuracy of various pellets at various velocities with barrels of different twist rates. All three barrels will be considered, but we’re really interested in the results of the two barrels supplied by Quackenbush. I can’t say that the factory barrel will be used as a control because it’s made differently than the two barrels Dennis has made (different rifling method and it’s choked). But the data will be included in the test report simply because it exists and may be of interest at some point. Any poential accuracy differences will be noted.
I’ll conduct this test at 25 yards and again at 50 yards. That will tell us how the different twist rates perform at different distances.
Test objective 2
Another factor that airgunners have talked about for a long time is the effect of twist rate on velocity. This discussion has been limited to big bore airguns because, as I’ve noted, all smallbores have the same twist rate. The popular theory is that a faster twist rate will result in a slower bullet velocity when everything else is the same. I’ll test the barrels at different power settings for each pellet I test.
What we’ll get from this test is a broad look at how the twist rate of a rifled barrel impacts (or doesn’t impact) the overall performance of pellets in a gun whose baseline performance we already know very well. I’ve thought long and hard about what would be the best way to conduct the test. Do I test the velocity first and then the accuracy? Or do I turn it around and test accuracy before velocity? I have a plan in mind, but I’d like your input before I start the testing. Remember that I already have a lot of good data on this rifle using the factory barrel.
As far as I know, an experiment like this has never been published before. Perhaps it’s been done, or perhaps parts of it have been done. If so, they didn’t put it in print. Neither Dennis nor I know how this will turn out. As he says, we’re pushing back the boundaries of ignorance in airguns.
I’d like to thank Dennis Quackenbush in advance for the work he’s done to make this test possible. I also want to thank AirForce Airguns for their part in what we’re about to do.
by Tom Gaylord, a.k.a. B.B. Pelletier
Before we start, you’ll remember that the president of Pyramyd Air promised to eat his hat if the IZH 60 I recently tested could not put 10 shots inside a quarter-inch group at 10 meters. It was close, but he lost the bet, so today we have two photos — one of the hat and the other of him eating it. Well done, Val!
Pyramyd Air President Val Gamerman eating the hat.
The caption to the first picture of the Talon SS PCP says it is a complete shooting system, and today we’ll look at another facet of that. Let’s look at the performance of the CO2 adapter, which turns the rifle from a PCP into a CO2 gun. Before this adapter existed, people were always asking for it. They envisioned it exactly as it turned out, but the demand went unanswered for several years. Then, Pyramyd Air negotiated with AirForce for a production run of adapters and we got them.
I’m running this report today because I need to use my Talon SS for a lengthy test that’s going to increase our understanding of the components of airgun accuracy. The rifle is the perfect platform for the test because it accepts barrels so quickly and easily. That test will begin soon, and I won’t tease you — everything will be fully explained when that test begins. But before I get to the heart of today’s report, a little history on the Talon SS.
How fast on CO2?
Now comes the question of the day. How does the Talon SS perform on CO2? Using the 14.3-grain Crosman Premier as the standard pellet, I was able to push them out the muzzle at 854 f.p.s. with the power setting on 10. That would be the number I would test against with CO2.
I used a full 20-oz. CO2 tank for this test. I tested the Premiers on both the lowest power setting and the highest. There shouldn’t be too much difference between the two settings, because CO2 is at much lower pressure than air, plus it flows slower than air; so at the same pressure, the velocity with CO2 will be less than with air.
On the lowest power setting, the average velocity for Premiers was 571 f.p.s. On air, it was 854 f.p.s. That’s a difference of 283 f.p.s. with air over CO2. But that was on the lowest power setting for the CO2, so how much does it change when I set the power as high as it will go? The average increases to 582 f.p.s. Not much difference, is there? The extreme spread on the low setting went from 568 to 574 f.p.s., and on high it went from 580 to 584 f.p.s. Since the low and high settings are so close, I decided to just keep the riffle on the low setting for the rest of the test.
At the average velocity (at the low-power setting), the pellet generates 10.36 foot-pounds of energy at the muzzle. On air, it generated 23.16 foot-pounds, or more than twice as much. That gives you a good appreciation of what the CO2 adapter does for the rifle. And remember, this rifle has a 12-inch barrel. If a longer barrel were installed, the velocity would increase somewhat, but not as much as with air. The optimum barrel length for CO2 is around 14-16 inches. After that, the velocity starts to fall again.
After the Premier, I tested the Beeman Kodiak heavy domed pellet. It weighs 21.1 grains and averages 506 f.p.s. in this gun on the low setting. It’s generating exactly 12 foot-pounds of muzzle energy at that speed. I don’t have the data for this pellet on air. The variation on CO2 went from 503 to 508 f.p.s.
Next up was the JSB Exact 15.9-grain domed pellet, which is the most accurate in this rifle. They averaged 567 f.p.s. on the low setting, which produces an average 11.35 foot-pounds of muzzle energy. On air at power setting 10, they average 823 f.p.s. The variation on CO2 went from 564 to 570 f.p.s.
The final pellet I tested was the RWS Hobby, which weighs 11.9-grains in .22 caliber. It averages 618 f.p.s. on the low setting and ranged from 614 to 621 f.p.s. The muzzle energy was 10.09 foot-pounds at the muzzle. And I don’t have a velocity for this pellet on air.
How many shots on a tank?
All I can tell you is that there are hundreds of shots per 20-oz. CO2 tank. The number is certainly more than we saw in any other test, and I would guess there are no less than 800 shots per tank. It’s one of those things that will vary each time the tank is filled, because no two fills will contain the exact same amount of liquid.
On CO2, the Talon SS is a 12 foot-pound rifle in 70˚F temperatures. It’s better-suited to all-day shooting and indoor plinking, though the Micro-meter tank gives it a fair run for the money. The accuracy of the rifle will not change, except that on CO2 it won’t have quite the same range as with air.
So, there you have the Talon SS in a 10-part report. To recap, we’ve looked at this .22-caliber rifle in stock trim, with a 24-inch barrel installed, with a Micro-meter tank and now with a CO2 adapter. There’s more to come, but it won’t be a test of the rifle. It’ll be a test that uses the rifle as the testbed. Now that you know how it performs, it’ll serve us very well in this new role.
Get a free CO2 adapter for Xmas
After I wrote this blog, I found out that AirForce is giving away a free CO2 adapter with the purchase of every Talon, Talon SS or Condor PCP air rifle. The adapter sells for $99.95, so that’s a nice gift! I understand that the giveaway ends Dec. 31, 2012.
by Tom Gaylord, a.k.a. B.B. Pelletier
We last looked at the .22-caliber Talon SS on June 13, when I told you that I had mistakenly shot the rifle with a standard air tank instead of a Micro-Meter tank in the previous test. I retested the rifle with an AirForce Micro-Meter air tank and the standard 12-inch barrel. Today, I want to finish the test with the optional 24-inch barrel.
You’ll recall in Part 8 that I shot the rifle 380 times on a single fill of the Micro-Meter tank. Today, we’ll see what difference, if any, we get from the 24-inch barrel. The only pellet used in this test was the .22-caliber Crosman Premier pellet.
Let’s begin — shots 1 to 10
The tank is filled to 3,000 psi and shooting starts. The power wheel is set as low as it will go. The first three shots go 429, 536 and 667 f.p.s., respectively. Shot four goes 726 f.p.s. and the rifle is stable from that point on. The first three shots were needed to wake up the valve. Discounting the first three shots, the string averaged 727 f.p.s. and ranged from 725 to 732 f.p.s., a spread of 7 f.p.s. The average energy was 16.79 foot-pounds; and yes, I’m aware that a Micro-Meter tank isn’t supposed to be that powerful. But we’re seeing the effect of doubling the barrel length in a precharged gun, and it’s dramatic!
Because of the large number of shots I expect to get from the tank, I then shot 30 shots without a pellet. I’ll call these blank shots.
Shots 41 to 50
This string averaged 715 f.p.s. and ranged from 711 to 718 f.p.s, so another 7 foot-second spread. The average energy was 16.24 foot-pounds. Then another 30 blanks were fired.
Shots 81 to 90
I shot this string on the highest power setting the gun has — just to see if there was any difference. There wasn’t. The average was 705 f.p.s. and the range went from 702 to 709 f.p.s. Another 7 foot-second spread. The energy was 15.79 foot-pounds. Then another 30 blanks were fired.
Shots 121 to 130
The gun was set back to the lowest power setting and remained there for the rest of this test. The average was 675 f.p.s., and the range went from 668 to 679 f.p.s. the spread was 11 f.p.s. The average energy was 14.47 foot-pounds. Then 30 more blanks were fired.
Shots 161 to 170
The average was 658 f.p.s., and the string ranged from 654 to 662 f.p.s. — a spread of 8 f.p.s. The average energy was 14.17 foot-pounds. Then 30 more blanks were fired.
Shots 201 to 210
The average was 641 f.p.s., and the range was 637 to 653 f.p.s. This string had a 16 foot-second spread. The average energy was 13.05 foot-pounds. Following this, 30 more shots without pellets were fired.
Shots 241 to 250
The average for this string was 618 f.p.s., and the string ranged from 613 to 621 f.p.s. So, a spread of 8 f.p.s. The average energy was 12.13 foot-pounds. Following this, 30 more blanks were fired.
Shots 281 to 290
This string averaged 594 f.p.s. and ranged from 581 to 601. So a 20 f.p.s. spread. The average energy was 11.21 foot-pounds. Then 30 more blank shots were fired.
Shots 321 to 330
The average was 561 and ranged from 553 to 568, and the spread was 15 f.p.s. The average energy was 10 foot-pounds. After this, 30 more shots were fired without pellets.
Shots 361 to 370
The average was 539 f.p.s., and the string ranged from 534 to 545. A spread of 12 f.p.s. was observed. The average energy was 9.23 foot-pounds. Another 30 blanks were fired.
Shots 400 to 410
Now we’re in uncharted territory. The gun is giving me over 400 good shots on a single fill. Clearly, the 24-inch barrel is a real boon to the performance of the MM tank. This string averaged 519 f.p.s. and ranged from 514 to 527 f.p.s. A spread of 13 f.p.s. The average energy was 8.56 foot-pounds. After this, 30 more blanks were fired.
Shots 441 to 450
The average was 497 f.p.s. and the string ranged from 489 to 504 f.p.s., for a total spread of 15 f.p.s. The average energy was 7.85 foot-pounds.
I could have continued to shoot the gun for many more shots, but I stopped at this point for a reason. After 450 shots have been fired, the Talon SS is still launching pellets slightly faster than my Diana model 27 breakbarrel. If that’s enough power for me, then this gun certainly gives all that and more. And I can’t think of another time when I shot 450 shots, unless it was for a test like this one.
The 24-inch barrel added significant performance
We all know that barrel length is important to a PCP, and this test makes that very clear. The 12-inch barrel gave 380 shots that ended up in the high 300 f.p.s. range. We’re still 200 f.p.s. faster than that after 450 shots have been fired! I think that establishes the Micro-Meter air tank as the champion of PCPs with the 24-inch barrel is installed.
In this series, we’ve looked at the Talon SS as it comes from the factory and with various modifications. The one we haven’t tried yet is the CO2 adapter, so that’s next. I’ll leave the 24-inch barrel installed since that’s the way I shoot the rifle all the time now, but I’ll test both velocity and accuracy with CO2 for you.
by B.B. Pelletier
Today is the day I tell you about the horrible blunder I made. Remember the two tests I did with the Talon SS PCP rifle using the AirForce Micro-Meter air tank? Well, that wasn’t a Micro-Meter tank! It was a standard tank!
Blog reader twotalon guessed it was wrong, and I ignored him. When John McCaslin, the owner of AirForce Airguns, read my last report of the Micro-Meter tank — the one where I got 340 shots on a fill — he saw that I reached over 800 f.p.s. in .22 caliber and knew a Micro-Meter tank couldn’t do that. He called me and walked me through the logic of why it couldn’t be a Micro-Meter tank. Sure enough, he was right!
I guess what happened is that when I went to AirForce to pick up the Micro-Meter tank, I grabbed the wrong tank. Then, when I tested it on the optional 24-inch barrel first, I didn’t question the numbers because I didn’t know what the numbers should be with the longer barrel. As for why I missed seeing it when I tested it with the 12-inch barrel, that was entirely my fault. I simply didn’t think it through. Twotalon even asked me if there was a sticker on the Micro-Meter tank, and I told him there wasn’t, but I thought that was because AirForce had forgotten to put one on. Or I’d picked up a tank before the sticker was applied.
It doesn’t matter. The fact is that I tested the gun with both barrels using a standard tank. I’m going to update those other reports to reflect that, and today we’ll see what a Talon SS does when it’s using a real Micro-Meter air tank. And now we have the results of a standard tank for comparison.
I’ll start today with the standard 12-inch barrel, and then I’ll test the real Micro-Meter tank with the 24-inch barrel in the next report. Because I have a good idea of how many shots I’ll get from this tank, I modified the test to shoot 30 dry-fire, or blank, shots between the recorded strings — just to burn up air a little faster. In the previous two tests, I fired only 20 dry-fire shots between strings.
I’m still shooting only the .22-caliber Crosman Premier pellet in this test. And I started with a fill to exactly 3,000 psi.
The first string of 10 shots was with the power wheel set at the lowest setting, which I’ll call zero. The gun averaged 590 f.p.s. and ranged from a low of 583 to a high of 601 f.p.s. That’s an average of 11.06 foot-pounds.
For the next 10, I dialed up the power as high as it would go. The rifle averaged 585 f.p.s. and ranged from a low of 582 to a high of 590 f.p.s. The average energy at the muzzle was 10.87 foot-pounds. Then, I fired 30 blank shots without pellets.
Shots 51-60 were fired on low power and averaged 557 f.p.s. They ranged from 547 to 563 f.p.s. The average energy was 9.85 foot-pounds. I fired 30 more blank shots. From this point on, all shooting was done on the lowest power setting.
Shots 91 to 100 averaged 547 f.p.s. and ranged from a low of 539 to a high of 556 f.p.s. They averaged 9.5 foot-pounds of muzzle energy. Notice how tight the strings are? Even though the velocity is decreasing, the consistency remains good. After this string, I fired 30 more blank shots.
Shots 131 to 140 averaged 525 f.p.s. and ranged from a low of 516 to a high of 533 f.p.s. The average energy was 8.75 foot-pounds. I noticed that the first couple shots at the beginning of each string were always the slowest, so those blank shots had an affect on the numbers. After this string, I fired another 30 blank shots.
Shots 171 to 180 averaged 512 f.p.s. and ranged from 502 to 523 f.p.s. The average energy was 8.33 foot-pounds. After this string, I fired 30 more blank shots.
Shots 211 to 220 averaged 489 f.p.s. and ranged from a low of 475 to a high of 500 f.p.s. The average energy was 7.59 foot-pounds. That puts the gun, after 220 shots have been fired, in the same power range as a .22-caliber Diana model 27. After this string, I fired another 30 blank shots
Shots 251 to 260 averaged 467 f.p.s., with a range from 458 to a high of 474 f.p.s. The average energy was 6.93 foot-pounds. After this string, another 30 blank shots were fired.
Shots 291 to 300 averaged 443 f.p.s. with a spread from 434 to 451 f.p.s. The average energy was 6.23 foot-pounds. The velocity is dropping off steadily, but slowly; and if you were plinking in the backyard, you’d never notice it. After this string, I fired another 30 blank shots.
Shots 331 to 340 averaged 416 f.p.s. and ranged from 410 to 425 f.p.s. The average energy was 5.5 foot-pounds. Another 30 blank shots followed this string.
Shots 371 to 380 averaged 379 f.p.s. and ranged from 370 to 392 f.p.s. The average energy was 4.56 foot-pounds. I stopped after shot 380 because the velocity was getting low and I heard a short hiss of air escaping from the tank. Clearly, the valve was down to its bottom performance point and would not continue to hold air at pressures much lower than this. When I checked the pressure remaining in the tank it was exactly at 1,100 psi. The gun used an incredible 1,900 psi of air over these 380 shots.
What have we learned?
The first thing we learned is that the gun gets even more shots with the Micro-Meter tank than it does with the standard tank. I count 40 more shots, though there were still some shots left in the standard tank when that test ended at 340 shots.
Next, we see there was no increase in velocity, as this tank was used up. Instead, there was a slow and steady decline in velocity from the first shot to the last.
As far as consistency goes, the standard tank was just as consistent as the Micro-Meter tank, but at significantly higher velocities. The Micro-Meter tank will be easier on your backstop. If that isn’t a problem, the standard tank still gives you plenty of low-velocity shots.
The last thing I’ve learned is that I’m still capable of making mistakes. I thought I was done with them several years ago, but apparently it’s like riding a bike. Once you learn how….
by B.B. Pelletier
The report that follows was done in error. I thought I was testing a Micro-Meter air tank, but it turned out that I was really testing a standard air tank.
The corrected test is located here. I am sorry for this inconvenience, but you can click on the link in the sentence above and it will direct you to the correct test.
Today, I’m testing the AirForce Talon SS with the standard 12-inch barrel using the Micro-Meter air tank. This is the setup the tank was designed to use; and although I predicted that this test would look a lot like the last test with the Micro-Meter tank and an optional 24-inch barrel, I was wrong. Today’s test is amazing! It’s an insight into how a precharged airgun operates.
I’ll begin at the end. I fired a total of 340 shots on just one fill, and there was still plenty of air remaining for at least another 150 shots! I saw first hand at the NRA Annual Meetings how the Micro-Meter air tank stays on the line for so long without needing a refill!
But don’t go cashing in those 340 shots just yet. Allow me to explain what I did and how the gun performed.
As before with the longer barrel, the tank was filled to 3,000 psi. That proved to be a mistake in this case. Allow me to show you what I mean.
This time, I didn’t fool around with any pellets other than the .22-caliber Crosman Premier. Everything you’re about to read was achieved with that single pellet.
First 10 shots
The first 10 shots were fired on the lowest power setting and averaged 392 f.p.s., ranging from 347 to 442 f.p.s. That is a large spread, and, as you’ll see shortly, the valve was partially air-locked.
The next 10 shots were fired on the highest power setting and averaged 849 f.p.s.! That’s correct, the gun produced 22.89 foot-pounds with the Micro-Meter tank at the highest power setting. The low was 836, and the high was 861 f.p.s. That was clearly not what this tank was designed to do, so I dialed the power back to the halfway point, which corresponds to about the No. 6 on the dial.
Power setting 6
At this setting, the rifle averaged 836 f.p.s., so I stopped at shot 5. The low was 832, and the high was 839 f.p.s. I wasn’t interested in this kind of power from the Micro-Meter tank, and I didn’t want to waste air. So, I dialed back to power setting 2 and continued.
Power setting 2
On power setting 2, the rifle averaged 786 f.p.s. Again, I stopped at 5 shots. The low was 758, and the high was 803 f.p.s. By this, time a total of 30 shots had been fired on the fill. I dialed the power down as low as it would go and continued.
The next 10 shots on the lowest power setting averaged 514 f.p.s. The spread went from 487 to 537 f.p.s. It was clear that the valve was now staying open longer, and I would estimate the tank pressure had dropped to 2,800 psi by the start of this string. I could see at this point that this was going to be a long test, though I never imagined how long; so, I shot twenty “blank” shots (dry-fires that had no pellets) just to use up some air. It’s arguable whether shots that have no pellet in front of them use the same amount of air as shots that do have pellets. As you’ll see, it really doesn’t matter that much because we haven’t even started yet!
The gun is still on the lowest power setting, and this 10-shot string averaged 574 f.p.s. The low was 550, and the high was 628 f.p.s. After this, I fired another 20 shots with no pellets.
The gun is still set at the lowest power. These 10 shots averaged 649 f.p.s. and ranged from 603 to 689 f.p.s. In retrospect, after the test was over, I determined this string to be the start of the useful shots. I estimate the tank had about 2,500 psi at the start of this string — though that would have to be confirmed if the numbers meant enough to you to do the work. They didn’t to me, so 2,500 psi was just my estimate. Now, I fired 20 more blank shots.
This string averaged 703 f.p.s. and ranged from 633 to 743 f.p.s. After this, I fired 20 more blank shots
This string averaged 750 f.p.s. and ranged from 719 to 766 f.p.s. I would like to note that the rifle is now performing almost exactly the same as a Beeman R1 breakbarrel in .22 caliber! When this string was finished, I fired another 20 blank shots.
This string averaged 752 f.p.s. and ranged from 743 to 757 f.p.s. This was the top power the rifle developed in this test, and I would estimate the pressure at the start of this string was around 1,900 psi. The gun will not use air in a linear fashion as the shots increase. As the air pressure in the tank drops, the valve stays open longer. I then fired another 20 blank shots.
This string averaged 735 f.p.s and ranged from a low of 727 f.p.s. and a high of 740 f.p.s. Notice how tight these later strings are! You could shoot at 35 yards with the gun shooting like this! And you could also hunt with it. I then fired another 20 blank shots.
This string averaged 713 f.p.s. and ranged from 707 to 726 f.p.s. The rifle is slowing down, but the valve is keeping each 10-shot string relatively tight. I then fired another 20 blank shots.
This string averaged 688 f.p.s. and ranged from 682 to 694 f.p.s. I then fired another 20 blank shots.
This string averaged 659 f.p.s. and ranged from 652 to 664 f.p.s. Notice how tight this string is after 300 shots have been fired! No other air rifle that I know of can do this when running on air. The USFT might be able to, but I haven’t tested it this way to see. I then fired another 20 blank shots.
This string averaged 624 f.p.s. and ranged from 613 to 630 f.p.s. This was where I stopped the test; but as you can see, the gun will still continue shooting for a lot longer.
Ending air pressure in the tank
After 340 shots had been fired, the Micro-Meter tank still had 1,200 psi remaining. That isn’t an estimate — I actually determined it by filling the tank and noting when it began accepting a charge. If my estimate about the pressure was correct when I declared the gun to be on the power curve (at shot 91), and if I include all the shots fired after that, then there were a total of 250 useful shots on a fill to 2,500 psi. The gun got those shots on about 1,300 psi of air. That is remarkable when you consider that it was also developing some pretty respectable power at the same time.
Remember what the Micro-Meter tank is for
To accept what I’m saying, you must keep in mind that the Micro-Meter tank is for shooting quietly in your basement. The range I envision is 10 meters, maximum, though we can see that the rifle can actually shoot a lot farther than that. But that’s not the purpose of the tank.
If the starting fill pressure is only 2,500 psi like I suspect, then the Micro-Meter tank can be easily filled from a hand pump. Another good thing about this novel air tank.
If you want to use the adjustable power feature of the gun, the range will be in the lower numbers. After the halfway point on the power scale, the rifle is just wasting air.
I’ve tested the Micro-Meter tank in the past, but never before with the mindset of its real purpose. Now that I have that in mind, this test has revealed an incredible level of performance.
Sure the velocity varied a lot over the useful shot strings; but at 10 meters, I doubt anyone will notice. For plinking and keeping the grandkids amused, the Micro-Meter tank is the lazy man’s PCP!
Next, I plan to test that theory with an accuracy test of this tank and gun combination at 10 meters.