Posts Tagged ‘AirForce Airguns’

AirForce EscapeSS: Part 3

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

AirForce Escape: Part 1
AirForce Escape: Part 2
AirForce Escape: Part 3
AirForce EscapeUL: Part 1
AirForce EscapeUL: Part 2
AirForce EscapeUL: Part 3
AirForce EscapeSS: Part 1
AirForce EscapeSS: Part 2

This report covers:

• 50-yard accuracy of Predator Polymags on high power.
• JSB Exact Kings accuracy.
• Kings on high-fill pressure.
• Benjamin domes.
• Kings on max power.
• Observations so far.

EscapeSS
AirForce EscapeSS

If you’re seriously interested in one of the AirForce Escape survival rifles, this blog series should be very beneficial. I’ve tested each rifle and attempted to get the best accuracy possible, using the best pellet. Last time, we looked at the rifle at 50 yards with the Predator Polymag pellet. Today, we’ll look at the EscapeSS accuracy at 50 yards using different pellets with the gun set to higher powers and greater fill pressures. Today’s test was an eye-opener for me.

The day at the range was windy, with a 5 m.p.h. breeze blowing all the time and gusting to 20 m.p.h. I waited for the wind to get as calm as possible, but all shots were in the wind. Sometimes, I took shots with the wind blowing up to 10 m.p.h. I think you can get away with that when shooting a .25-caliber pellet gun, though it’s not ideal.

Predator Polymags at higher power
In Part 2 of the EscapeSS, I shot the rifle at power settings 6 and 7 and with the reservoir filled to 2000 psi and 2200 psi. That was done because testing with both the Escape and the EscapeUL rifles demonstrated that the Predator Polymag pellet was the most accurate. Those rifles also seemed to be most accurate with their reservoirs filled to 2000 psi.

I said at the end of the last test that the Predator Polymag pellet still had to be tested at higher power and with a 3000 psi fill, so that was the first test on this day. I filled the gun’s reservoir to 3000 psi and dialed the power to 8. Then, I shot 5 Predator Polymags.

EscapeSS power 8
The power was set to 8, but as you can tell from the dial on the left, this is not a precision setting.

The results were not very promising. Instead of the 3/4-inch to 1-inch groups I got last time, this time 5 Polymags went into 1.526 inches. While that’s acceptable for hunting at 50 yards, I’d hoped to get better accuracy from this rifle.

EscapeSS Predator target power 8
When the power and pressure were raised, the Predator Polymag pellets started to scatter at 50 yards. Five went into 1.526 inches.

JSB Exact King
For the next group, I wanted to try something that was way out of the box. I filled the reservoir to 3500 psi and left the power setting on 8. That’s more pressure than the factory recommends, but I’ve read some reports from other shooters that say the gun does well with this kind of fill. I wanted to see. This was the first time I was trying JSB Exact Kings in this rifle.

The impact point shifted up about 4 inches, and 5 Kings landed in 1.387 inches. The rifle actually shot better with this pellet at this higher pressure; although, with a 12-inch barrel I doubt that there was much more velocity.

EscapeSS JSB King target 1 power 8
Five JSB Exact Kings went into 1.387 inches at 50 yards on power setting 8 and a fill of 3500 psi.

Having one good target, I decided to try it again with the same setting and fill pressure. This was to see if the first group was a fluke. This time, 5 Kings landed in 1.588 inches, which is close enough to the first group to say this is about what the rifle can and will do with these settings. This time, though, I adjusted the scope to get the pellets on target.

EscapeSS JSB King target 2 power 8
The second try with Kings at a fill of 3500 psi and power 8 gave me this 1.588-inch group.

Now, I decided to follow the manual and fill to just 3000 psi. I left the power setting on 8 — and 5 Kings went into 1.077 inches. Almost a one-inch group!

EscapeSS JSB King target 3 power 8
The fill pressure was lowered to 3000, and the power stayed on 8. Five Kings went into 1.077 inches at 50 yards!

That was so surprising that I filled the rifle to 3000 again and shot a second group, also on power setting 8.  I noted that the shots did drop a bit, so I adjusted the scope again. This time, 5 Kings went into 1.233 inches. So close to the first group that I think this is where the rifle wants to be.

EscapeSS JSB King target 4 power 8
The second try with Kings and a 3000 psi fill on power setting 8 gave me this nice 1.233-inch group. This is a good setting for this pellet.

I also noticed something interesting that illustrates a point I’ve been making for years. The gauge on this particular rifle does not agree with the gauge on my carbon fiber tank. When the tank gauge reads 3000 psi, the rifle’s gauge is off the scale! This illustrates how some small pressure gauges can be off by a lot, which is why you pick one gauge to follow — in this case, the one on my carbon fiber tank — and go by it all the time.

EscapeSS  pressure gauge
When the carbon fiber tank gauge reads 3000 psi, this is what the rifle’s gauge says. This is only on this particular rifle. The other Escape gauges read pretty much the same as the carbon fiber gauge. The point is that small pressure gauges can differ a lot.

Benjamin dome
Now it was time to see what the rifle would do with the Benjamin domed pellet. I kept the power at 8 and the fill at 3000 psi, and 5 pellets went into 1.667 inches. That sort of turned me off after seeing what the Kings could do, so I didn’t shoot a second group. Sometimes, you just know when one pellet is better than another.

EscapeSS Benjamin dome target power 8
Benjamin domes seemed to open up at these power and fill settings. These 5 measure 1.667 inches between centers.

JSB Kings at max power
It was time to try the JSB Exact Kings at maximum power and a 3000 psi fill. I shot 5 of them into a 1.831-inch group. As I was finishing this group, the wind was picking up to the point that I had to shoot in 10 m.p.h. wind and higher. I finished the day with these results:

EscapeSS JSB King target 5 power max
The last target was shot with Kings on a 3000 psi fill and poower set at max. It measures 1.831 inches between centers, but the wind was really picking up when it was shot.

Observations so far
I was surprised that the EscapeSS liked a higher power setting and fill pressure than either the Escape or the EscapeUL. Perhaps, that’s because of the shorter barrel, whose muzzle is so close to the front barrel bushing. I don’t know, but it underlines the need to test these adjustable rifles in many ways and with many pellets.

All 3 Escape rifles are for survival, though they can be used for hunting by anyone. Hunters typically use very few actual shots. The only exception would be when eliminating pests like rats or pigeons. The Escape rifles have small reservoirs that allow easy filling from a hand pump. I’ve found all 3 rifles to be well-suited to their role, but each has different qualities that the shooter may enjoy. With the EscapeSS the big difference is how quiet the rifle is. It’s not as quiet as some PCPs, but it’s also a good deal more powerful than most of them.

I’m still planning to report on the velocities of the 3 Escape rifles at their optimum power settings, so there’s more to come.

AirForce EscapeSS: Part 2

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

AirForce Escape: Part 1
AirForce Escape: Part 2
AirForce Escape: Part 3
AirForce EscapeUL: Part 1
AirForce EscapeUL: Part 2
AirForce EscapeUL: Part 3
AirForce EscapeSS: Part 1

This report covers:

• How loud?
• Experience with .25-caliber Lothar Walther barrels.
• First accuracy test of the Escape SS.
• What’s next?

EscapeSS
AirForce EscapeSS

Today, we’ll start looking at the accuracy of the AirForce EscapeSS. Unlike other accuracy tests, this one didn’t start at 10 meters or even at 25 yards. I went right out to the rifle range and shot the rifle at the 50-yard backstop.

When you have an air rifle with the power of these Escape rifles, you have to take it outdoors. Unless you have a very special place to shoot, this is an outdoor air rifle.

How loud?
But with that said, the EscapeSS is also the quiet version of the rifle. So, I didn’t wear hearing protection at the outdoor range. I knew the gun wouldn’t be loud enough to hurt my ears, and I wanted to be able to tell you how loud it is. I did not fire the rifle on full power for today’s test, but all the shots sounded very restrained. I would say it was louder than a Benjamin 392 on 8 pump strokes, but not as loud as a Benjamin Discovery in .22 caliber. It’s a sound you can hear, but it isn’t as sharp as a .22 long rifle or even a .22 short.

Experience with AirForce .25-caliber Lothar Walther barrels
To this point in time, I’ve tested the Escape and the EscapeUL — both in .25 caliber. The .25 caliber doesn’t have many accurate pellets, but testing these rifles and the TalonP pistol has revealed a few. One of them stands out as the absolute best. The Predator Polymag pellet in .25 caliber is hands-down the most accurate pellet I’ve tested in these Escape rifles, and my observation agrees with the Escape’s co-developer — Ton Jones.

I cut right to the chase and used the Predator Polymag pellet exclusively in today’s test. I’ll try other pellets in future tests — but, for today, I shot only this one.

Setup
The other experience I have with the Escape rifles is that they’re most accurate with fill levels of 2,000 psi and a power setting of 6. That’s how I set up the rifle for the first group.

I removed the Bushnell Banner 6-18X50 scope from the EscapeUL and mounted it on the EscapeSS in a BKL 1-piece mount and, without even sighting in, I started shooting at 50 yards. I’d planned on sighting in, but my first pellet struck the bull I was aiming at, so there was nothing more to be done. Apparently the EscapeUL and EscapeSS are very similar!

I shot 5-shot groups, because I have found the Escape rifles to be most accurate within a 5-shot band. Sometimes, this will stretch to 6 or even 7 shots, but that’s about all if you’re shooting groups at 50 yards. And I’m shooting groups so small they prove the rifle for hunting purposes! This is not some generalization or extrapolation of accuracy. I’m reporting what these rifles can do in the field.

The first 5 shots went into 1.197 inches at 50 yards. The group was off to the left of the bull, with just the first shot in the black.

EscapeSS first group
First 5 Predator Polymags at 50 yards went into 1.197 inches. This was without sighting-in the rifle — just mounted the scope and started shooting!

With these same settings, the worst group of 5 went into 1.341 inches, and the best 5 went into 0.975 inches. That’s 3 groups that average 1.171 inches. That is about what the rifle does on this setting.

EscapeSS second group
Second 5 Predator Polymags at 50 yards went into 1.341 inches. Of the 3 groups on this setting, this was the worst.

Next, I boosted the fill pressure to 2,200 psi and left the power setting at 6. I got 2 groups — one that was 0.903 inches and the other that was 1.63 inches. That’s a big difference.

EscapeSS third group
Bumping the fill pressure to 2,200 psi and leaving the power set on 6, I put 5 Predator pellets into 0.903 inches — the second-best of this test. But the very next group using the same settings opened up much larger.

Next, the power was increased to 6, and the fill pressure remained at 2,200 psi. I got one group at 1.638 inches, which turned out to be the worst of the test, and a second at 1.077 inches.

I dropped the fill back to 2,000 psi and left the power at 8. This gave a group measuring 1.185 inches.

After that, I dropped the power to 7 with a fill pressure of 2,000 psi. The first group measured 0.778 inches, and the next one measured 1.444 inches. The 0.778-inch group was the best of the entire test.

EscapeSS fourth group
These 5 Predator pellets went into 0.778 inches — the best of this test. That ragged hole at the top is a pellet hole that has partially closed.

Analysis
How do we make sense from these results? It seems the rifle is capable of shooting 5-shot groups smaller than one inch at 50 yards, but the average is slightly larger than one inch. Only one group in this test was as large as 1.50 inches, which I think says a lot about the stability of the .25-caliber Predator Polymag in this rifle.

I didn’t test the other 2 Escape rifles this way, but the results I got with both of them do seem to fit this pattern. It was only because of those results that it was possible to cut through the maze of pellets, pressures and power settings and get these results so fast.

Of course, I haven’t tried this pellet at full power, yet, nor have I tried the rifle with a 3,000 psi fill. I think that has to be tried — just to say that it was done.

The rifle also needs to be tested with other pellets; although, if the groups it gets are similar to those gotten with the other 2 Escape rifles, we may begin to understand that all .25-caliber Lothar Walther barrels perform similarly.

When the other accuracy testing is completed, I’ll test all 3 Escape rifles for their velocities with the most accurate pellets. That would be the information I would want as a hunter.

Evaluation of the EscapeSS
The EscapeSS is closest to the TalonP pistol that sired all three Escape rifles. You would expect the performance to be identical, except that this rifle is both quieter and comes standard with an adjustable buttstock. If you’re looking for quieter performance in a survival air rifle, the EscapeSS might be the one for you.

AirForce EscapeSS: Part 1

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

AirForce Escape: Part 1
AirForce Escape: Part 2
AirForce Escape: Part 3
AirForce EscapeUL: Part 1
AirForce EscapeUL: Part 2
AirForce EscapeUL: Part 3

This report covers:

• Summary of the AirForce Escape report up to this point.
• There are three different air rifles.
• EscapeSS is quieter.
• EscapeSS description.
• How does the EscapeSS differ from the TalonP pistol?
• What comes next?

It’s been a while since we last looked at the AirForce Escape air rifles. To date, we’ve seen the power, accuracy and general characteristics of the AirForce Escape and the EscapeUL, which is the ultra-light version. Today, we’ll start looking at the EscapeSS, which is the version of the rifle with some sound muting.

We’ve seen that the Escape rifles can generate tremendous power — up to 97.88 foot-pounds of muzzle energy from the Escape rifle when the heaviest .25-caliber pellets are used. We’ve also learned that the Escape rifles are at their most accurate when the fill pressure is lowered and the power is dialed back. That held true for both the Escape and the EscapeUL, so it seems to be a trend; and I’ll use that experience when testing the EscapeSS.

There are three rifles!
Before moving on, I want to emphasize there are three different air rifles. The Escape, EscapeUL and EscapeSS all have different specifications and deliver different performance. I’m telling you this because customers are starting to run the model names together and getting confused over which rifle does what.

EscapeSS three rifles
The three Escape rifles are the Escape (top), the EscapeSS (center) and the EscapeUL (bottom).

Each of these air rifles is unique and different from the others. The Escape is the most powerful of the bunch. The EscapeUL is the smallest and lightest, and the EscapeSS that we’re looking at today is the quietest of the three.

If you forget how the first two rifles performed, I urge you to go back to the reports linked above and catch up. I intend reporting on just one rifle in this report — the EscapeSS.

EscapeSS
The EscapeSS is a smaller rifle with a 12-inch barrel inside a frame that acts as a shroud.

Quieter rifle
The SS is the quiet version of the Escape — just like the Talon SS is the quiet Talon and the CondorSS is the quiet Condor.

To achieve this quieter report, the EscapeSS has three baffles ahead of its muzzle. They’re held tight in the frame by a Belleville washer ahead of the last baffle and behind the end cap.

EscapeSS baffles
Inside the EscapeSS shroud/frame are three Delrin baffles and a Belleville washer to keep them from rattling.

I’ve already been to the range and can report that the EscapeSS really is quieter than either the Escape or the EscapeUL. It has the same recoil of the other two, which is greater than the recoil of a medium-weight .22 rimfire rifle, but the sound is greatly reduced.

However — just because the muzzle report is greatly reduced from the Escape does not mean the EscapeSS is a quiet rifle. While it’s much quieter outdoors than a .22 rimfire, it’s also louder than a Benjamin 392 pumped 8 times. The EscapeSS is not for suburban backyards! It’s more of a quieter hunting air rifle for public lands. I doubt it would be noticed beyond a half-mile away.

The EscapeSS description
The EscapeSS is a precharged pneumatic air rifle that comes in both .22 and .25 calibers. It has a 12-inch Lothar Walther barrel; but like all AirForce sporting rifles, it can accept barrels of any length. It can also accept other calibers, but I don’t believe I’d try one in .177 caliber because this powerplant is so overwhelmingly powerful that it would be hamstrung by such a small bore size.

The rifle weighs 4.3 lbs., and its length varies from 27.75-inches to 32.25-inches — depending on how the shoulder stock is adjusted.

The rifle is made on an aircraft aluminum frame that houses all the parts, including the barrel. The 213cc air reservoir can be filled to 3,000 psi, nominally giving about 10 powerful shots. Like all AirForce sporting air rifles, the EscapeSS has adjustable power via an adjustment wheel located on the left side of the frame.

How does the EscapeSS differ from the TalonP pistol?
I have to address this issue before the questions start flooding in. Sharp observation will notice that both the EscapeSS and the TalonP have the same 12-inch barrel (that comes in both .22 and .25 calibers), and they share the identical powerplants. So, what makes them different?

First, the TalonP frame is shorter. This makes the gun smaller, but it also means there’s no room for the baffles. The TalonP is louder than the EscapeSS at the same power.

Next, the TalonP comes without the extendable shoulder stock. You can purchase one as an accessory if you like, but the basic pistol comes without it. The EscapeSS is a rifle that comes standard with the shoulder stock.

The EscapeSS and TalonP should both develop comparable power when they’re set up the same way. But the TalonP is more compact, and the EscapeSS is more of a carbine-length rifle. You have to decide which is best for you. You can always add the shoulder stock to a TalonP, but you cannot make it as quiet as an EscapeSS.

As I said, I’ve already been to the range with the EscapeSS. I used the experience obtained when testing both the Escape and EscapeUL rifles instead of testing every pellet in the rifle. And I knew beforehand that the fill pressure and power settings needed to be lowered, so I started low and worked around until I found the best combination.

EscapeSS power
We know that the EscapeSS has a 12-inch barrel. Knowing how barrel length affects velocity, we know that the velocities for this rifle are going to be lower than for either of the other 2 rifles. But when I tested the rifle, I discovered something I didn’t expect.

All these tests used the 43.3-grain Eun Jin pointed pellet. On high power with a 3,000 psi fill, the first 5 shots gave the following results.

Shot Vel.
1     785
2     776
3     763
4     749
5     739

This gives an average of 763 f.p.s for the first 5 shots. At the end of the shooting, the tank pressure still read 2,500 psi. At the top velocity (shot 1), this pellet produces 59.26 foot-pounds of muzzle energy. At the average velocity, this pellet produces 55.99 foot-pounds.

I then dialed the power setting to 8 and refilled the tank to 3,000 psi. That gave the following results.

Shot Vel.
1     784
2     763
3     759
4     748
5     736

That gives us an average velocity of 756 f.p.s. Not very different, is it? The tank pressure after these 5 shots read 2,400 psi. At the top velocity, the muzzle energy was 59.11 foot-pounds. At the average velocity, the energy was 54.97 foot-pounds.

Then, I dialed down the power to 4 and got a huge surprise. That gave the following results.

Shot Vel.
1     801
2     779
3     767
4     758
5     741

The average velocity for this string was 769 f.p.s. — the highest in the test! At the top velocity, this pellet produced 61.70 foot-pounds of muzzle energy. At the average velocity, it made 56.87 foot-pounds! So, the rifle was more powerful on power setting 4 than it was with the power wheel dialed up as high as it will go. The rifle’s ending tank pressure read 2,500 psi.

The 12-inch barrel is showing up in these results. Clearly the rifle is wasting air with this pellet when the power is set above a certain low number. I think the number is around 4, but it would take more testing to know for sure.

That’s as much velocity testing as I’m going to do now because it isn’t helpful. I’ll come back and do a more thorough velocity test when I know which pellets this gun likes. With this gun, it isn’t just about power. Accuracy is also very important. The best combination of both is what we’re looking for.

In my next report, I’ll show you the results of the first accuracy test, which are very encouraging.

The next step in testing the Escape rifles
After we complete testing the EscapeSS rifle for accuracy, we’ll start the next phase of testing for all 3 rifles. That will be testing their velocity at the most accurate setting with the most accurate pellet or pellets.

Following that, I’ll install a .22-caliber barrel in the Escape and test that. If I see enough difference between the Escape and the Condor, we may do more testing in that caliber, but I don’t know yet. It’s too far into the future to know for sure.

Why choke a barrel?

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

This blog was requested by blog reader Joe, who wanted to know if choked airgun barrels are more accurate, and why. A number of other readers seconded his request. So, we know there’s interest in the subject.

What is a choke?
A choked barrel is one in which there’s a reduction in the diameter of the bore near the muzzle. Someone likened it to the FX Smooth Twist barrel that’s rifled only at the end of the barrel, but it isn’t the same. The Smooth Twist barrel has a constriction — the rising of the rifled lands. But in a choked barrel, the entire bore gets smaller. I don’t know if the Smooth Twist barrel is also choked; but if it is, that’s a separate thing.

Most shooters know that shotguns are choked, and they understand why. A choke keeps the shot from spreading as quickly as it would without a choke. Shotguns have several specific kinds of chokes that make the pattern they project contain a certain shot density at a given distance from the muzzle. Hitting something at 25 yards with an improved cylinder choke is virtually the same as hitting it at 40 yards with a full choke. But that’s not what a choke does for a rifle barrel.

A choked rifle barrel squeezes the bullet or pellet slightly just before it leaves the muzzle. This is only an analogy, but it’s like pulling hard on a dog’s leash — it gets his attention and focuses him. In the case of the bullet and pellet, it stops any minute fluttering that may be happening inside the bore.

In my experience, it does work. Here’s what I know. First, the great barrel maker, Harry Pope, always choked his barrels. He first drilled the holes in the barrel blank undersized, then reamed the bore to get a choke of half a thousandth of an inch (0.0005-inches or 0.0127mm). His choke was an even taper down the full length of the barrel; and for the life of me, I can’t comprehend how he did it. Most barrel makers have a transition point where the bore tapers more or less abruptly from one size to the smaller size. This transition is very smooth, and the choke is seldom more than a thousandth of an inch, so it doesn’t disturb the bullet or pellet that much.

Pope’s barrels are legendary. One of them put ten lead bullets into 0.20 inches at 200 yards! And a great many of them will put 10 shots into a half inch at 200 yards, although Pope never guaranteed that level of accuracy.

But what about today’s barrels? Are they choked and does it help? Yes and yes are the answers. But not all barrels are choked — and even those that are choked may not be so intentionally.

Here’s a true story. When AirForce Airguns was switching over to Lothar Walther barrels in the early days, they tried barrels with and without chokes. Lothar Walther was capable of making barrels without chokes; but in their conversations with AirForce, they asked why they wanted unchoked barrels. After testing, AirForce decided it was well worth the additional cost to have all their barrels choked.

In the three years that I worked at AirForce, I tested every rifle that was returned to the company for inaccuracy. That must have been 20-30 rifles, in all. Every time one came in with such a complaint, the first thing I did was clean the barrel with J-B Non-Embedding Bore Cleaning Compound, and the next thing I did was shoot a group with the clean barrel. In all that time, I only had to shoot a single group with each barrel to produce a 5-shot group that ranged between 0.25 inches and 0.375 inches at 23 yards (which was the longest straight distance I had inside the old factory). Then, the rifle was packed with the target that I signed and dated and returned to the customer. Case closed.

Only once in three years did I find a barrel that I couldn’t get to shoot. It was an 18-inch .22-caliber Talon barrel that I’d cleaned several times. It just would not group better than 0.75 inches at 23 yards. It stumped me until I pushed a pellet through the bore with a cleaning rod, starting at the breech. There was no choke! Somehow, this barrel had slipped through the Lothar Walther manufacturing process without getting a choke, and it would not shoot.

Unintentional chokes
So far, I’ve been talking about chokes that are intentionally put into the barrels, but there are the unintentional kind, as well. Certain spring rifles such as the HW 80 and older versions of the Beeman R1 used to come with sights. The barrels of those rifles had dovetail grooves for the front sight swaged into the front of the barrel. When the swage upset the outside of the barrel to make these grooves, the metal inside the bore was distorted just a little at the same time. If you push a pellet through these barrels, you’ll feel it pause when it gets to where the dovetails begin. This isn’t a real choke, but it does feel like one when you test for it this way. Shooters have referred to these as choked barrels for decades.

swaged dovetaiul grooves
You’re looking at the end of the dovetail grooves (those small v-shaped nicks on both sides of the top of the barrel) that were swaged into this R1 barrel to attach the front sight. When this is done, the force of the swaging process upsets metal inside the bore, making it feel like a choke — but it really isn’t.

Spring guns probably don’t need to be choked. When they fire the intense blast of air they generate, it irons the pellet’s skirt out into the bore. As long as the barrel remains uniform throughout its length (and not all barrels do), the pellet is fit to the bore by this action. But a pneumatic or a gas gun releases its compressed air or gas more gradually and doesn’t distort the pellet. So, a choked barrel is the way to make all pellets uniform before they leave the muzzle of these airguns.

How are barrels choked?
Years ago, chokes were put into barrels with reamers just before they were rifled. In other words, the choke was cut directly into the metal of the bore. But with the advent of button- and broach-rifling, it’s easier to rifle the barrel first and then squeeze it down afterwards.

I read with interest where one of our readers was advising someone that a barrel had to be annealed before choking it by the squeezing method, and then hardened afterward. Actually, air rifle and rimfire barrels are made from dead soft steel, or steel that is nearly dead soft. They are not hardened in any way and can be distorted very easily. You could choke a barrel by tapping the outside with a ball peen hammer — though it won’t be uniform, and I certainly don’t recommend trying it.

Chokes can be rolled into barrels with hardened steel rollers set in fixtures that apply force gradually. Someone asked if a tubing cutter would work for this, and I have the answer. No, it won’t work. It will crimp the barrel, but it’s too sloppy and difficult to control a hand tool like a tubing cutter. I know this because I had Dennis Quackenbush convert a tubing cutter for me several years ago, and I attempted to choke barrels this way. But a precision jig that applies equal force to precision rollers that are similar to the function of  a tubing cutter is certainly one good way to choke a rifle barrel.

Another way is to run the barrel straight into a tapered die and swage in the choke — similar to resizing a cartridge during reloading, only a lot more force is required. To do it that way requires that the outside of the barrel be held to very close tolerances, so it’s less desirable than the tapered roller method.

A third way to choke a barrel is to squeeze it together from the outside, using a die made in two pieces. The pieces come together, compressing the barrel between them. Like the other method that uses a die, this method also requires a barrel of a given outside diameter.

If you hammer-forge the barrel (cold-forming the barrel around a hardened mandrel that has the rifling pattern in reverse), the choking can be done when the mandrel is made. Simply make the mandrel with a taper, and the barrel that’s ironed around it will also be tapered.

Companies select the method of choking that suits their barrel manufacturing methods. In other words, if they make hammer-forged barrels, that’s the most convenient time to put in the choke. But if they sell only one choked barrel for every thousand barrels they make, rolling in the choke probably makes more sense.

Quick and dirty
Here are some facts from this report.

1. Choked barrels do seem to shoot more accurately — all other things being equal (meaning the barrels are of equally high quality).

2. Not all rifled barrels are choked.

3. Spring gun barrels may have chokes that are unintentional.

4. There are several different ways of choking a barrel.

5. Companies select the most cost-effective way to choke the barrels they make.

Summary
While you may feel compelled right now to run out and find a way to choke every rifled barrel you own, remember this — it may not be necessary. Some barrels that are not choked do just fine the way they are.

However, having written this report, I find that I am now thinking about choking the barrel on my BSA Meteor to see if that helps with the mediocre accuracy.

The AirForce top hat

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

This report was requested by blog reader Rob 8T2 and seconded by a number of others. I reported on the spring piston forward spring guide that’s known as a top hat, and he wondered if I was also going to talk about the AirForce top hat. Though they share the same name, the two items aren’t connected in any way. One is a spring guide, and the other is an adjustable valve stem for a pneumatic valve. The adjustable valve stem draws its name because, like the forward spring guide, it also looks like a gentleman’s top hat in profile.

AirForce Airguns old top hat
The sliding breech cover has been pushed forward, cocking the striker and revealing the breech for loading. This is the original valve from a first-generation AirForce Talon without a power adjustment wheel.

To understand the AirForce top hat, we have to go back in time to before AirForce Airguns air rifles had power adjustment wheels on the left side. In January 2000, I reported on the new AirForce Talon, the first air rifle to be offered to the U.S. market by the new AirForce company. But I’d already owned the rifle I tested for two years. I bought it from the UK company, GunPower, in 1998, when it was configured differently and sold as their Stealth rifle. In late 1999, AirForce Airguns sent the parts to reconfigure my rifle to their new Talon specification, with an 18-inch .22-caliber barrel.

By that time, I already had many hours of testing and shooting on the rifle in its original Stealth configuration with its 12-inch barrel. It was during that time, by talking to AirForce owner and creator John McCaslin, that I learned how to adjust the top hat of my rifle to change the power.

You may find it amazing to learn that I could adjust that rifle to fire from 65 f.p.s. all the way up to 950 f.p.s. with 14.5-grain Eley Wasps. In truth, any velocity below about 400 f.p.s. was just a parlor trick. The rifle could do it, but all consistency was lost. From 400 to 950, though, it was fairly consistent.

How the top hat power adjustment worked
Power was adjusted by screwing in the top hat to shorten the valve stroke and the valve dwell time (the time the valve stayed open). The valve stroke became shorter because the wide flange at the base of the top hat contacted the top of the valve body and stopped moving. Then, the valve return spring started pushing the valve stem closed again, aided by the high-pressure air inside the reservoir.

Conversely, a longer valve stroke meant more dwell time and more air flowing out. At some point, however, the pellet left the 18-inch barrel, and the longer valve stroke stopped having any additional influence. Once the pellet’s out of the barrel, no amount of additional air can push it any faster.

To loosen the top hat for adjustment, unscrew a tiny 0.050″ Allen screw in the large knurled bottom flange of the hat, allowing it to turn on its threads. Once the desired clearance was reached, the small screw was tightened again. This screw caused problems because enthusiastic owners were over-tightening it, causing it to put dents in the hollow valve stem it contacted. In later years, AirForce started putting two screws in this flange to increase the locking pressure and hopefully reduce the damage to the valve stem.

The o-ring secret
Adjusting the top hat was a chore. One day, airgunsmith Tim McMurray told me about an easier, more convenient way. He said to slip a rubber o-ring around the top hat flange, so it rode in the space beneath the flange. It very effectively limited the amount of valve stem travel. Once I found out how good it was, I left it in place all the time. I wasn’t interested in sheer velocity. I wanted good accuracy at a reasonable level of power. Nothing has changed in 14 years, has it?

AirForce Airguns Talon SS top hat
The closed breech of this very early Talon shows where the o-ring goes.

AirForce Airguns Talon SS breech open
Here you see the breech open for loading.

Talon SS puts an end to top hat adjustment
In November 2000, I wrote about the new Talon SS, which was the first AirForce rifle to have a power adjuster on the left side of the gun. My own SS was a pre-production prototype that didn’t have the power scale engraved on the side of the rifle; but after 14 years of continuous use, it’s still working fine and the air tank has never leaked.

AirForce Airguns Talon SS power adjuster
All AirForce sporting PCPs now have this power adjustment wheel.

The Talon was also updated with the power adjustment wheel at the same time. Now all AirForce sporting PCPs have power wheels and the top hats no longer need adjustment.

John thought that the power-adjustment mechanism would put an end to the fiddly top-hat adjustment, but it didn’t! By the time the power adjuster came on the market, there was a lot of interest in AirForce Airguns…and the internet was abuzz with homebrew ideas of how they should be set up and operated. People did use the new adjustment, but they also continued adjusting their top hats. Top hats continue to be adjusted and discussed right down to today!

The truth about the top hat
The truth is that the top hat is still a very influential part of the AirForce system. It does have tremendous impact on the rifle’s operation, though not always in the ways you read on the internet. Now that the rifles have the power adjustment wheel, the top hat has become more of a starting point or a setting that gives each rifle a potential range of power. The power adjustment wheel is what fine-tunes that range. The top hat is a set-and-forget kind of adjustment, only people are not leaving it alone.

Some valve stems are very thin, such as those found on the Hi-Flo valves. When the screws are over-tightened on these valves, they dimple all too easily. That’s one reason I advise owners not to adjust their top hats.

Top hats are set at the factory with feeler gauges. I’ve told several people I once discovered that an American quarter coin was exactly the right thickness to set the top hat for a Condor Hi-Flo valve. I’ve actually done that more than once. A difference of one or two thousandths of an inch from the factory spec usually isn’t critical. But when the difference grows larger than that, it does start to become critical. It depends on which rifle you’re talking about to determine if the difference is critical.

For the record, I left AirForce Airguns in 2005, and a lot of things have changed since then. I’m not qualified to give out factory specs on anything they make today. I don’t adjust my top hats at all. I use the power adjuster 100 percent of the time when I adjust, and most of the time I leave each gun set at the position that gives me the greatest accuracy.

You wanted to know about the AirForce top hat — there you go.

Common PCP leaks and some common fixes

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

I’m still in Ft. Smith, Arkansas, as I write this, so please excuse the brevity of the report. A while ago, I wrote down this idea as a possible report topic. Those who haven’t yet come over to PCPs often wonder how reliable they are, and those who already have the guns sometimes encounter things that are common problems but new to them. Let’s talk about that today.

WARNING: The procedures I am about to describe are for those who know what they are doing. In every case, there are proper safety steps to be taken so accidents don’t happen. I cannot possibly describe all of those steps, so the following procedures are presented only for your education — not to train you as an airgunsmith. Safety with pressurized air and airguns should always be the No. 1 concern.

I can’t fill this airgun!
Boy, have I ever heard this one! It can come to you in a variety of ways, such as, “This airgun is broken — how do I return it?” I used to get at least one of those calls every month while I was the technical director at AirForce Airguns. The first few times I heard it, I was worried; but I got so used to hearing it that I would start telling them the cure before the problem had been fully stated.

The guy would tell me that he couldn’t fill his old-style Condor tank. I asked him how he was trying to fill it — from a scuba tank or with a hand pump — and a lot of times that made the guy mad. He wanted to know why that mattered because he should be able to fill the gun from a scuba tank or from a hand pump. Right? When this call came in, I knew he was filling with a hand pump, and I also knew he was trying to fill an empty tank.

The answer to “can it be done” is both yes and no. Yes, you can fill this kind of tank from a hand pump if there’s already some air inside it, and no, you can’t fill the tank if you start with it empty. That would really anger some people until I explained that the air inlet valve on an old-style Condor tank is also the exhaust valve. It’s a door that swings both ways. If there’s no air inside the tank, the valve will not recognize the small puff of air from a hand pump and will escape, again.

The valve will not close because it also uses internal air pressure to help it close tight. If you fill the tank from a scuba tank, the incoming air is under so much pressure that it will fill the tank quickly, and the internal air pressure will help close the valve when the filling stops.

A hand pump cannot fill some pneumatic airguns (not just Condors) unless they already have some air pressure inside to hold the inlet valve closed. We would ship tanks out with what we called a maintenance air charge in them — just enough pressure to hold the valve shut. But if the guy received the gun and then proceeded to shoot all that air out, as some of them did, they then had a gun that could only be filled from a scuba tank. It’s not funny when it happens to you.

This phenomenon is not just confined to AirForce guns, either. Almost all of the powerful Korean airguns work in a similar way. But the Korean guns can accept a charge by simply cocking the bolt — sometimes. In that case, taking the pressure of the bolt off the valve allows it to close and seal completely.

The newer style of Condor (as well as all other AirForce sporting PCP rifles) has a Spin-Loc tank with a separate inlet valve and firing valve. I’m not certain, but I believe this has solved the problem I just discussed. If I had a tank and pump here with me, I would check it right now. I’ll look into it when I get home.

Now you know two things about PCP “leaks” that are both very common problems and often misunderstood. First, they aren’t really leaks. They’re part of the gun’s design. Second, some guns must first be cocked to be filled.

Before you go all — “They shouldn’t design them that way!” on me, remember, the SR-71 Blackbird reconnaissance plane leaks fuel until it flies fast enough to heat and expand the airplane’s skin. Only then do all the leaks stop. Sometimes, a product can have a quirk that isn’t a flaw — it’s just the way it works. The Sheridan Supergrade rifle is one that cannot be pumped up unless the bolt is cocked first.

Use a hammer!
I probably shouldn’t tell you guys this next one; because when some of you get a hammer in your hands, every problem looks like a nail. But in the world of pneumatics, there are times when a big rubber mallet is exactly the right tool to use. When is that time? When a pneumatic that has been performing well all along suddenly develops a fast leak. It’s probably due to a piece of dirt that’s gotten onto a soft seal and is allowing air to pass through. To get it off the seal, it sometimes works to tap the end of the valve with a soft hammer. It opens the valve, and the blast of air will probably blow the dirt past the seal.

When I built valves at AirForce, I tested each by pressurizing them in a fixture and tapping the valve stem with a rubber hammer. I had racks of 100 valves at a time, and I went through and did this to each one in turn. That process seated the valve and created a small ring of contact between the synthetic valve and its seat. Sometimes, the valve needed to be hit several times to seat it properly, but it always worked. And it also worked if a valve had a small piece of dirt anywhere in the seals.

When customers would call with a gun that leaked and I determined the leak was a fast one that had popped up all of a sudden, I told them to try this procedure before sending the tank back for repairs. It fixed probably over 75 percent of all such leaks.

But this isn’t magic. If your gun has been a slow leaker the whole time you’ve owned it, this isn’t going to change a thing. It’s just for those all-of-a-sudden leaks that crop up sometimes. It will work for all guns, but most of them don’t allow direct access to the valve head like the AirForce tanks do. For those, you can do the next best thing — dry-fire the gun several times. That usually fixes the problem unless you’re timid about it. I sometimes had to get a timid owner to dry-fire his gun by telling him to fill it full and then dry-fire it 20 times in rapid succession. All that was doing is getting him to dry-fire the gun repeatedly without pausing to see if it was fixed yet. When there’s a piece of grit on a seal, it takes a lot of air flowing past to dislodge it, and a couple tries are often not enough. Twenty shots is probably overkill in all situations, but it saved me time from having to explain in detail just what the guy was doing — as I have now done for you!

You now know a genuine airgunsmith procedure! It isn’t as fascinating as it sounded, is it?

Listen
Okay, let’s go back to 1960, when cars had points and copper spark plug wires with (sometimes) poor insulation. Mechanics had a genuine stethoscope in their toolboxes. Or if they were shade-tree mechanics, like me, they had a 4-foot length of small rubber hose. We would put one end of the tube to our ear (the ear that worked best) and move the other end around the engine compartment while the motor was idling. You could quickly zero in on an arcing sparkplug wire or an exhaust manifold leak. It also works for precharged airguns!

You don’t need a hose because the barrel is the pipe that transmits the sound. Cock the gun but don’t load it. The sound you’re listening for is an air leak at the exhaust valve. But here’s an important safety tip — never put your ear directly over the muzzle and never do this if the gun is loaded! Listen from the side of the muzzle; so if the gun were to fire, the air would blast past your ear instead of into it! You can use a piece of paper to direct the sound, if needed. That keeps you safe and still lets you hear the smallest sounds.

I’ve found a number of valve leaks this way. This is just a diagnostic tool — it doesn’t do anything to fix the valve.

If your ears aren’t that good, or if you just don’t want to do it this way, you can also put a few drops of soapy water down the muzzle of a cocked gun. Bubble-blowing solution that you can buy at a dollar store works perfectly for this! If any air is escaping the valve, there will be bubbles at the muzzle. I always had a small bottle of bubble-blowing solution next to me when I worked on guns at AirForce. Of course, you have to clean the barrel and wipe it with an oily patch after doing this.

These little procedures have proven very valuable over the course of time. If the situation is right, they’ll fix the problem more often than not. While they seem simple to the point of being somewhat ridiculous, they do work.

AirForce EscapeUL: Part 3

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

AirForce Escape: Part 1
AirForce Escape: Part 2
AirForce Escape: Part 3
AirForce EscapeUL: Part 1
AirForce EscapeUL: Part 2

EscapeUL
The AirForce EscapeUL is a lightweight PCP with the Escape powerplant. Everything has been modified to save weight.

I’m still in Ft. Smith, Arkansas, filming segments for this year’s American Airgunner TV show, so today’s report will be short. After I reported the 50-yard accuracy test for the EscapeUL, blog reader Gunfun1 asked me if I had remembered to coat the pellets with Slip 2000 oil that Ton Jones likes. I had to admit that I’d forgotten, so I promised him I would. Last Friday, I went to the range and shot the EscapeUL with just the 2 best pellets — the 43.2-grain Eun Jin pointed pellet that develops the maximum power in the rifle, and the Predator Polymag pellet that was the most accurate on lower power.

Predator Polymag
The first pellet I shot was the Predator Polymag. I did that because the rifle was still set on the same power setting I used in the last test. If you recall, I shot 2 groups of Polymags that time. One was 5 pellets in 0.622 inches at 50 yards. I thought that was phenomenal! The second group of 5 opened up to 1.298 inches, but I shot it in a continuous wind. I just waited for quieter moments, but the wind was always blowing for that group.

Oiling the pellets
I put several drops of the Slip 2000 lube on the foam that JSB packs in the tops of their tins. Predator Polymags are made by JSB, so they always have this foam. Then, I put some pellets on the foam and rolled them around until they were moist to the touch.

The first target I shot looked like it was going to beat my earlier best group; but after 3 shots, the rifle threw the next shot to another location, opening the group much larger. Okay, I thought, maybe I didn’t get the fill pressure just right. I continued shooting until there were 6 shots on this target. The entire group measures 1.545 inches between centers. That isn’t bad; but in light of what I did before with unoiled pellets, I wasn’t happy with it.

EscapeUL with Predator Polymag pellets
Six oiled Predator Polymag pellets made this 1.545-inch group. The first 3 shots were at the upper left.

This group suggested to me that the EscapeUL doesn’t like oiled pellets. It seemed like once the bore was oily, accuracy went south. Of course, I couldn’t let it ride without testing it once more. This time, the pellets were oiled in the same way, but the bore was already oily. I mention that because the next group of 5 wasn’t nearly as good as the first. Five Predator Polymags went into 2.634 inches! And that was what I expected would happen. When I saw the pellets in the previous group opening up, it was something I have seen before. Oiled pellets often do this, in my experience.

EscapeUL-predator-group-2
Five more oiled Predator Polymag pellets made this 2.634-inch group. From what I’ve seen, this is pretty common with oiled pellets, though sometimes they’ll shoot better than they do when dry.

The wind was starting to pick up, so I switched from Polymags to Eun Jins. This time, I ran the power up as high as it would go and filled the reservoir to 3,000 psi. The last time, I shot 5 dry Eun Jin pellets into a group that measured 1.866 inches at 50 yards. That set the bar for the oiled pellets.

And the challenge was met! I got an almost-identical 1.862-inch, 5-shot group with the oiled Eun Jins. The measurement error is larger than the difference between these 2 groups!

EscapeUL-Eun-Jin-group
Five oiled heavy Eun Jin pointed pellets went into 1.862 inches at 50 yards. That’s so close to what they did when dry that it’s too close to call.

Sometimes, you win…and other times not
I know this isn’t a huge test with lots of controls and numerous targets. But I didn’t think oiling the pellets was actually going to help. From what I see here, it didn’t. It’s just one extra step for little or no return. I certainly would not oil the Predators, again!

The one advantage I see with oiling is that it makes the pellets load easier. At least it does for the Predators. The Eun Jins load very hard no matter what you do. I had to use the flat side of the screwdriver blade on my pocket knife to get them into the breech — even after oiling!

I doubt I’ll oil pellets for this rifle again.

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