Posts Tagged ‘bolt-action’
Crosman’s 160: Part 3
by B.B. Pelletier

Fresh from the closet, another fine Crosman 160 emerges into daylight. We’ll watch this one blossom.
Today, I’m testing the Crosman 160 for accuracy. This is a target rifle — originally intended for 25-foot ranges, so 10 meters, which is very close to 33 feet, is the distance I shot for this test. And I shot at 10-meter rifle targets. It’s important to remember this rifle is a .22, not a .177, because the larger pellets will influence the overall group size.
The 160 has a post front sight that isn’t as precise as an aperture, but I learned to shoot on a similar sight, so it still works well for me. I’d disassembled the rear aperture sight during cleaning, so when I sighted-in there was a lot of adjusting to get the pellet on target.
I held my eye as close to the aperture as I could get, because my recent experience with both the Ballard and Remington model 37 has taught me that this is the way to get the best accuracy from an aperture sight. The tiny hole made my pupil dilate and the front sight came into sharp focus, as it always should.
I sighted-in with the JSB Exact 15.9-grain dome and left the sights there. So, the first group is well-centered and the other pellets are a little bit off.
Remember that wonderful trigger I told you about last time? Well, this is where it came into its own. It is breaking so light that I leave my finger off the blade until the sight picture is correct. Then it’s just touch and “Bang!” It breaks at a pound. I’ve bump-tested the gun several times without a pellet just to see if I could jar it off the sear, and it’s holding fine…but it feels like a precision set trigger. Perhaps, having the overtravel adjustment makes the difference.
Memories!
I remember these 160s as being more accurate than they have a right to be, given their original price, and this one is, too. The first 10 shots went into a group that measures 0.313 inches. The group is very round and gives every indication that the rifle loves this pellet.

Ten JSB Exact 15.9-grain domes made this 0.313-inch group at 10 meters.
Next, I tried the .22-caliber Premiers. Back in the early 1990s, when this pellet first came out, 160 owners discovered their rifles were much more accurate than they had believed. When the 160 was new, it was thought that the best they would do was a quarter-sized group at 25 feet. Now they were shooting into a dime at 33 feet.
This time, the group wasn’t as good as some others I’ve shot. Ten shots measure 0.449 inches between centers. The point of impact shifted to the left a bit, as well.

Ten .22-caliber Premiers made this 0.449-inch group at 10 meters.
I also wanted to try a pellet I’d never used in a 160, so the next pellet was an RWS Superdome. They should do well, being both medium weight and thin-skirted. A thin skirt can be blown out into the rifling by the low pressure of the CO2 gas, which will seal the pellet in the bore quite well.
Before you get excited from looking at these next targets, you need to know that I was interrupted while shooting and as a result I put 5 shots on each target, instead of the 10 on one, as planned. Although this was a mistake, it does illustrate, once again, the difference between the sizes of 5-shot and 10-shot groups.

If you didn’t know there were only 5 shots in this group, you could make up all sorts of claims for the RWS Superdome pellets. The group measures 0.107 inches between centers. This is 10-meter target rifle size — even though it was shot with the larger pellets! But it is only 5 shots.

Five RWS Superdomes measure 0.313 inches between centers. Looks good, but, again, it’s only 5 shots. This group was fired when I noticed the gun was running out of gas.
As I loaded and shot, I reflected on the ease of the bolt’s operation. Opening it requires just the flick of one finger, because you’re not cocking a spring. It’s as quick as pulling back the bolt on a biathlon target rifle. Pushing the bolt forward takes some effort, though, because this is where the hammer spring gets compressed.
The big .22-caliber domed pellets lie in the loading trough and feed without a bobble. Where some guns want to flip pellets around, the 160 feeds them effortlessly every time. I can describe the cocking and loading experience as having an oily smoothness.
Best pellet
Upon examination, I feel the JSB Exact pellet did the best in this test. It put 10 pellets into a group the same size as the final 5 Superdomes made. It would be interesting to shoot another group of Superdomes that were not shot at the end of the gas supply, but I still think the JSBs will turn out better.
Shot count
I noticed on the final 5 shots that the rifle sounded like it was losing power. Since 5 shots were used for sight-in, this rifle has given me 35 good shots on two cartridges. Blog reader Jim in PGH commented that an Archer Hammer Debouncer Device (abbreviated HDD and designed to give the valve stem a dead blow to exhaust gas without valve flutter) installed on a Chinese version of the 167 (a .177-caliber version of the 160) that he owns has increased his shot count to 80. That would be worth looking into, if you decide to go the 160 route.
Where are we?
As I shoot the 160, I cannot help but think of a fine 10-meter target air rifle. Kevin would be proud to shoot one so fine. I think most of you would be impressed with what this gun can do.
This is the last report I have planned for the 160. As I suspected, the owner of this 160 was not too keen about the two CO2 cartridges needed to power his gun, so he sold it to me. I have no plans for it at this time, other than to show it to several firearms shooters to impress them with what an airgun can do. I’m also toying with shooting it at 50 yards, just to see how it does.
Crosman’s 160: Part 2
by B.B. Pelletier

Fresh from the closet, another fine Crosman 160 emerges into daylight. We’ll watch this one blossom.
Today, I’ll report on the cleaning of Jose’s Crosman 160 and the adjustment of the trigger. This rifle was quite rusty when I got it, so today it came out of the stock for a thorough cleaning. The barreled action comes out of the stock by removing one nut on the bottom of the forearm and by removing the safety switch. To remove the switch, it must be turned toward SAFE while you push it out of the triggerguard. It will pop right out when you get it in the right position.

The broken safety has been pushed out, and the nut removed from the stock. That’s a new safety to the left of the broken one. The barreled action is now ready to come out of the stock.
Once the action was out of the stock, I could see that it was far rustier than I originally thought. The rust that could be seen when the rifle was intact was just surface rust, but the stock was hiding deep active rust that had to be removed.

This was under the stock — heavy, active rust that must be dealt with!
I used Ballistol and a special scrubbing pad I bought at a recent gun show. A friend of mine says this pad looks like a stainless steel pot scrubber. All I know is that it removes all the rust and doesn’t harm the blue.

I used Balistol in a spray bottle and a special metal scrubber to remove the rust.
I was surprised at how fast the rust was removed. In all, it probably took no longer than 15 minutes to completely clean all the metal parts.
The trigger
With the gun finally clean, it was time to address the trigger. I mentioned in Part 1 that this trigger is one of the finest ever put on an inexpensive air rifle, and it can be adjusted to a very light, crisp pull. When I got the gun, the single-stage trigger had lots of creep and was breaking at 5 lbs., even. Something had to be done about that.
The Crosman 160 trigger is an adaptation of a 15th century crossbow trigger, where a rotating piece called a nut forms the sear that releases the hammer — in the case of the pellet rifle. The nut is a lever that’s shaped like a circle. It allows a small force (the sear) to overcome a greater force (the hammer spring) through leverage. No filing or stoning of the trigger contact surfaces is necessary, because the trigger doesn’t work like a conventional one.

From Sir Ralph Payne-Gallwey’s book, “The Crossbow,” (published in 1903) this illustration of a 15th century crossbow nut shows how a great force can be overcome by a smaller one.
But the Crosman 160 trigger is more sophisticated than the crossbow trigger. It allows the adjustment of the sear contact area and also the point at which the trigger stops. This gives the shooter a safe trigger that breaks cleanly, yet feels like an expensive precision target trigger.

The trigger in the subject rifle was about as filthy as I’ve ever seen. This trigger has a sideplate that allows the user to watch the adjustments of the parts and even to cock and fire the trigger with the parts exposed. Normally, this sideplate keeps the parts inside pretty clean, but you can see from the photo what I saw inside this one.

I’ve removed the trigger unit from the action here. It isn’t necessary to do this, and in fact you must be able to cock the rifle when you adjust the trigger, so leave it connected. I did this for cleaning purposes.

Compare this photo to the previous graphic, and you’ll see all the important trigger parts. This is before cleaning. The rusty red part at the upper right is the nut that’s the sear.
I removed the trigger blade from the trigger assembly and cleaned it outside the trigger box, but all other parts were cleaned where they were situated. Ballistol on cotton swabs worked wonders at removing the rust, dust and dirt. And it left all the parts with a lubricated surface.
The two trigger adjustment screws were stuck in place by dried grease, so Ballistol had to dissolve that before I could clean the threads. The final touch was to apply moly grease to the mating surfaces of the trigger blade and the rotating nut that serves as the sear. Then it was time to adjust the trigger.
Trigger adjustment
The first step was to back off the trigger return spring, which is located at the bottom rear of the trigger box. With this spring relaxed, you can feel the engagement of the sear much better.
Next, I adjusted the top screw, which adjusts the trigger/sear contact area. I set it very quickly because I’ve adjusted dozens of these triggers over the years and I know what they need. You may have to adjust the screw then cock the rifle and fire it several times to get the engagement you want. The engagement needed is very narrow, and it looks like the trigger is about to slip off the sear; so I always give the cocked rifle a bump test after adjusting the trigger, just to be safe. If I can’t jar the trigger off the sear, it’s safe.
The final screw to adjust is the trigger stop or overtravel screw. It stops the trigger blade after the sear has released, and the closer this is to the release point without impeding the trigger-pull, the better the trigger feels. Once the engagement area is okay, it’s easy to set this screw to stop the trigger immediately following trigger release.
With that done, I put the cover plate back on the trigger and shifted my attention to the S331 sight. By the way, Robert of Arcade explained in a comment that the S331 sight was actually made by Mossberg and not by Williams, as I originally said in Part 1. I changed the maker to Mossberg in Part 1, and now I’m telling you.
The rear sight on this rifle was loose when I examined it, so I removed it from the rifle and disassembled it for cleaning. Most of the parts are aluminum, but a couple are blued steel and suffered from rust to the point that there were pits left on their surfaces after the rust was removed. The detents are very crisp and easy to feel as you make the adjustments. This is a simple peep sight assembly, but it works very well and adjusts precisely, which is all you can ask of a sight.
Once the sight was clean and back on the rifle, I put the barreled action back into the stock. I had to use the old broken safety switch because the replacement I have is slightly too large to fit the hole. I’ll trim it down in a separate session so the gun has a complete safety switch. For now, I’ll just keep the rifle off safe.
How does it look?
Because the bulk of the deep rust lies below the stock line, the deep pits that appeared from cleaning do not show. What was above the stock line was mostly just surface rust that’s now completely gone. The metal on this rifle now appears to be 80 percent or better. The stock finish is still flaky and needs to be taken down all the way with sandpaper and reapplied, but it doesn’t detract from the rifle’s appearance.
And the trigger?
The trigger now breaks at one pound, even. It’s glass-crisp, and you would swear that it releases at just a couple ounces if you didn’t see the trigger-pull gauge. I think the owner will be amazed at the transformation this rifle has undergone.
Yet to come
I won’t bore you with the other mundane jobs like the safety and the stock finish, but I’ll test this rifle for accuracy. So, there’s one more report yet to come. We already know the velocity is in the right ballpark — 656 f.p.s. for a 14.2-grain Daisy pellet on a 90-degree day. But I want to show you the accuracy these old rifles can give with modern pellets.
Crosman’s 160: Part 1
by B.B. Pelletier
Announcement: Jacque Ryder is this week’s winner of Pyramyd Air’s Big Shot of the Week on their airgun facebook page. He’ll receive a $50 Pyramyd Air gift card. Congratulations!
Jacque Ryder is this week’s BSOTW.

Fresh from the closet, another fine Crosman 160 emerges into daylight. We will watch this one blossom.
I was at the rifle range yesterday, and a friend delivered an air rifle that another friend had asked him to give me. It’s a Crosman 160, and that’s a classic air rifle that I’ve never reported in this blog, so here we go.
History
The Crosman 160 and 167 (.22 caliber and .177 caliber, respectively) was first produced in 1955 and lasted until 1972. There were several variations of the basic model over the years, but most airgunners rank them by their triggers. There was a very simple trigger in the first variation from 1955 through 1959, then Crosman put out a very special variation with a super-adjustable trigger in the guns made after 1959. The gun I’m testing has this wonderful trigger.
At some time in the 1960s, the Air Force bought a large number of 160s that were fitted with a Crosman S331 peep sight (made by Mossberg) and sling swivels that held a one-inch leather sling. As chance would have it, several hundred of these rifles were discovered unused in a government warehouse in Maryland or Virginia in the 1990s, and Edith and I bought one. It was brand new and still contained the original Crosman CO2 cartridges that had been used to test it at the factory. I knew they were original cartridges because they were sealed with the patent-dodging “bottlecap” tops Crosman had to use for several years. The end flap of the box had the Air Force Federal Stock Number for the gun, and everything inside the box was new and untouched.

Still rusty and dusty from long years of storage, the Crosman S331 peep sight is a great addition to this accurate target rifle.
I reported on that 160 in The Airgun Letter several times, but eventually I got rid of the rifle. And until yesterday, that was all I had to do with a Crosman 160.
A shooting friend of mine told me a couple months ago about an airgun he had, and from his description I guessed that it was a 160. Yesterday, he sent it to me so I could examine it and tell him what he has. Jose — I have your rifle, and it’s a Crosman 160!
Yours is the last variation they made, which in all ways is the best 160 model to have. It isn’t a former military model, because they all have sling swivels and your rifle has no evidence of ever having them. But you do have the adjustable trigger and the S331 peep sight.
Your rifle has a lot of surface rust that I’ll remove with Ballistol and a special scrubbing pad I’ll show you in the report. I’ll also open the sideplate on your adjustable trigger and clean and adjust it for you. If it’s like the other 160 triggers I’ve adjusted in the past, I should be able to get a glass-crisp trigger-pull of a little less than one pound. I think you’ll be surprised!
Barrel lottery
Back when these air rifles were new, people thought they were only capable of putting 5 shots into a quarter at 25 feet. What we didn’t appreciate back then were the poor pellets we used held us to that level. Once world-class pellets became available in the 1980s, everything changed and these rifles suddenly became capable of putting 10 shots inside a dime at 10 meters. That is — if they had a good barrel.
Crosman made the barrels for the 160s. When they were good, they were very good. But when they were bad, they were horrible! I’ve heard tales of barrels with only half their rifling and even some that had no rifling at all! It isn’t common, but it happened often enough that old Crosman collectors know about it.
Pellgunoil works, again!
I installed two fresh powerlets and a LOT of Crosman Pellegunoil, and the gun held gas. I then fired 5 shots at a 50-yard target, just to see what kind of barrel it had. I got a group of about 5 inches, but it was a windy day and all I was trying to do was see if the barrel was rifled or not. It is. When I shoot it for accuracy, this rifle should do very well.
The safety switch is broken, which means I’ll have to use pliers on it, because it’s key to disassembling the rifle. The good news is that some plastic aftermarket safety switches exist and I may be able to locate one.
Gas-guzzler
The big problem with a 160 is that it uses gas like a Hummer towing a house trailer! Typically, the two CO2 cartridges give about 30-35 good shots before they give out. Since they cost at least 50 cents apiece, a 160 can cost more than a .22 rimfire shooting good ammunition.
The solution is to convert the rifle to bulk-fill operations. That reduces the gas cost per fill to around 5-7 cents per fill. You still get the same number of shots and the same velocity, but the operating cost is much lower. Of course, you have to have all the equipment that’s needed for bulk-fill to do this, and that does cost some money.
Power
Most 160s I’ve tested pushed 14.3-grain pellets out the spout at between 600 and 630 f.p.s. on an 80-deg. F day. It was about 90 when I shot through the chronograph at the range and the 14.2-grain Daisy pointed pellet (very similar to the current Precision Max) went through the Oehler skyscreens at 656 f.p.s. — right on the money! The rifle can be souped up a just a bit, but at the cost of increased gas usage. There’s really no convenient way around that.
By contrast, the Crosman 180 was a single-cartridge rifle that shot a .22-caliber pellet at around 575 f.p.s. and got about 40 good shots per cartridge. It was the favorite of many shooters. But the Air Force obviously didn’t care about how much CO2 they used, and the slightly more powerful 160 also had a better stock, a longer barrel and better sights. It was the obvious choice for a target rifle. I feel the procuring agency must have bought the gun, not so much for its accuracy but more for its much safer operation when compared to a standard .22 rimfire that was the normal target rifle of the time. A pellet rifle range could be set up safely in a gym, where a rimfire range required more safety measures.
General description
The Crosman 160 is a .22-caliber single-shot CO2 rifle. It cocks on closing the bolt. It needs two CO2 cartridges to operate, though it will work with just one at lower velocity and with fewer shots.
The rifle weighs 6 lbs. and is 39-1/2 inches long. The barrel is 21 inches. The pull is 14-1/4 inches.
The rifle is mostly blued steel in a solid wood stock. The metal was not highly polished and I’ve always thought that the wood stock was some very clever kind of laminate, since it shows more grain than I think it should. I will show you the detail and let you be the judge.

The stock sure looks like a laminate to me.
What’s next?
I plan to clean the metal of this rifle and preserve it with Ballistol. I’ll open the sideplate of the trigger and show you the inner workings, then I’ll adjust the trigger to get it working as fine as I can.
Next, I’ll test the rifle for velocity with several pellets. I’ll also get a shot count for you.
Finally, I’ll shoot the rifle for accuracy at 10 meters with several pellets. I’ve examined the barrel, and the bore appears sparkling clean. The rifling is deep and everything looks okay. We should have some fun with this one.
Jose, you have a very nice air rifle, here. I hope you enjoy this report!
Winchester M14 .177-caliber dual-ammo air rifle: Part 2
by B.B. Pelletier

Winchester’s new M14 dual-ammo rifle looks very much like the military rifle it copies.
Let’s test the velocity of the Winchester M14 dual-ammo rifle. Of course, I’ll test it with both BBs and lead pellets. This rifle is a semiautomatic 8-shot repeater powered by 2 CO2 cartridges. Someone made a comment that referred to the rifle having blowback action, but I want to clear that up — it doesn’t. Yes, the action operates by CO2 power and really is semiautomatic; but no — there’s no sensation of blowback, and nothing moves when the rifle fires.
You do have to pull the “bolt” back to cock the rifle before the first shot. It’s not really a bolt — just a plastic cover to hide the metal internal parts of the firing mechanism. But the act of pulling it back is realistic.
The stick mag has an 8-shot rotary clip on each end. After firing 8 shots, you pop it out and reverse it for another 8. Then, you must reload the magazine. I see no reason why you can’t carry additional loaded magazines, as long as you take some care to keep them clean. They do have moving parts that affect their function, so these parts have to be able to move or the gun will jam.
BBs first
I tested the rifle with Daisy zinc-plated BBs first, and discovered that the rotary clips have a magnet inside to hold the BBs in place. Because the chambers in the clips are for .177 pellets, they’re too large for BBs — which are .173-caliber. But the magnets securely hold the BBs in place.
BBs averaged 560 f.p.s. and ranged from a low of 546 to a high of 580 f.p.s. That’s a pretty broad spread for a CO2 gun. It’s also 140 f.p.s. slower than the advertised top velocity of 700 f.p.s., which surprised me, because the BBs are very light and are possibly the fastest projectiles this gun can shoot. This BB weighs 5.1 grains and generates 3.55 foot-pounds of muzzle energy, on average.
The stick mag dropped out of position two times during the test, which entailed just over 40 shots. I’ll chalk that up to my not seating it correctly for now, but it’s something I plan to watch as the test progresses. I note that there’s a click deep inside the gun that must be heard to know the magazine is seated correctly.
Now pellets
The first pellet I tried was the JSB Exact RS. As light as this domed pellet is, I felt it would compliment the power of this airgun well.
This 7.33-grain lead pellet averaged 519 f.p.s. and ranged from a low of 507 to a high of 542 f.p.s. At the average velocity, it generated 4.39 foot-pounds of muzzle energy.
Next, I loaded RWS Hobby pellets. At just seven grains, I expected them to be the velocity champs among the pellets, but they turned in a disappointing average of 491 f.p.s. The spread, however, ranged from a low of 443 f.p.s. to a high of 532 f.p.s., indicating the gun was running out of gas. This was after fewer than 30 shots had been fired! Well, it’s possible that I shot it more times while writing Part 1 and just didn’t remember it.
I installed two new CO2 cartridges; and as the old ones were expelled, they both lost a lot of gas. The rifle was not firing at this point, so a lot of gas was being wasted. I kept track of each shot these new cartridges gave, so I could report the total shot count.
With the new cartridges in place Hobbys gave an average 549 f.p.s. The spread, though, was still very large, extending from a low of 507 to a high of 592. Since the first four shots also expelled a cloud of CO2 vapor, I know they were artificially higher than the average, which was more in the 520 f.p.s. region.
I don’t know what to make of these velocity numbers. Clearly, Hobbys were all over the place, depending on how new the CO2 cartridge was. I would guess their average is really closer to 520 f.p.s., which would give them an average muzzle energy of 4.2 foot-pounds.
I must also note that Hobbys were too large to seat in the chambers of the circular clip easily. I had to use the Air Venturi PellSet to get them into each chamber far enough for the clip to rotate freely. Perhaps, that might explain their erratic behavior.
The next pellet I tested was the Crosman Premier 7.9-grain dome. These averaged 472 f.p.s. in the M14, and the velocity spread went from 457 to 482 f.p.s. At the average velocity, this pellet averaged 3.91 foot-pounds of energy at the muzzle.
Trigger pull
I mentioned in Part 1 that I felt the trigger was close to a military pull. Well, it breaks at an average 6 lbs., 5 oz., so it’s just a little heavier than the standard 5-lb. military pull. The pull is a little creepy, but it’s not bad. I will probably have more to say about it after the accuracy test.
Shots per fill
We’re using two CO2 cartridges in this rifle. So how many shots does that give? I disregarded the early cartridge swap and started counting after the new cartridges were installed.
I got a total of 112 shots before feeling it was necessary to change the cartridge. That’s a good number for everything else this gun does. Let me tell you how it went.
I used mostly JSB Exact RS pellets for this test, so I could see where the power was at any given time. After the first 40 shots, the gun no longer shot above 500 f.p.s. It stayed around 470 until shot 88; but if several shots were fired quickly in a row without giving the gun time to warm up again, the velocity dipped down to almost 400 f.p.s. Stop shooting a minute, though, and it’s back to 470 with the RS pellet.
After shot 88, the rifle dropped below 400 f.p.s. for the first time and started slowing down. If 5 shots were fired rapidly the velocity at the end was only 312 f.p.s. After shot 104, the gun was always in the 300s. I stopped at shot 112 because I felt the gun could jam if I went too much farther. Shot 112 was fired after a minute’s pause and went 335 f.p.s.
Impressions so far
This rifle is turning out to be somewhat different than I thought at the beginning. It isn’t as consistent as I’d hoped. It suffers too much velocity loss from the cooling effect as the gun shoots. That will be expressed as vertical stringing on any targets. The best accuracy will come by pausing a minute between shots.
Accuracy is next. I am very curious as to what we will see.
Oops! My Benjamin 397 has valve lock!
by B.B. Pelletier

The Benjamin 397 (left) is a powerful multi-pump. Obsolete 397 carbine at right.
Today, we have a critical report about airgun maintenance and operation. So, if we’re being critical, let’s start with the title. It’s a It’s no one’s fault — let’s all get along title. It should read, Oops! I really screwed up! And when I say “I,” that’s exactly what I mean!
About a month ago, a friend of mine — who shall remain nameless, unless he repeates what I am about to tell you — received a new Benjamin 397 multi-pump pneumatic. Hurray!
I went over all the operational and maintenance steps carefully with him — pump it no more than 10 times per shot, always store it with one pump in it, use Pellgunoil on the pump head etc. — and then turned him loose with his new rifle. Last week the rifle came back to me with the complaint that it didn’t fire pellets anymore.
I must have looked like that old plumber who knows just where to tap the pipe to get the system going again, because before I even examined the rifle I told him it was over-pumped and therefore valve-locked. Then, I took the rifle and opened the pump handle, which sprang open with a lot of force. Yep — it’s valve-locked, all right!
I listened carefully to the story of how it couldn’t possibly have been anything that he did wrong. I’ve heard that same story a hundred times before; but like a compassionate priest, you have to let them confess everything as you listen in silence. On about the third go-round, I got the real story.
It seems he was at work, shooting his new gun with a buddy who was also shooting his own multi-pump. Remember, folks, we’re talking Texas, here. Depending on your job, shooting at work isn’t that uncommon. Perhaps not at a funeral home or at a fast-food franchise, but there are a lot of outdoor jobs where shooting is possible and not objectionable.
They were shooting at a metal sign that the buddy’s gun wasn’t able to dent very much, but the 397 put a big ole’ dent in it. However, something wasn’t right! It seems the other guy’s pump gun was much easier to pump than the 397. What was wrong with the 397?
What was wrong with it was that it wasn’t a Crosman 760, like the other guy’s gun! At least that’s my guess. I’m still waiting to hear what the other guy’s gun was.
So, his new gun was harder to pump, but it was also a lot more powerful. MAYBE he wanted to see if the 397 would go all the way through the sign, thus vexing his friend, which is the tradition whenever two guys shoot together. He pumped it ALL the way up, being VERY CAREFUL not to exceed the 10-pump limit, as I’d instructed him. But that time it fired only weakly.
He handed his rifle to his friend, who then pumped it up again, also being VERY CAREFUL not to exceed the 10-pump limit, because the owner was watching him. This time when the trigger was pulled, the gun just went CLICK and no pellet came out. So, now he knows that his gun doesn’t work anymore.
At least he stopped when it got to this point. He didn’t keep loading pellets and pumping it a couple more times just to be sure. I have seen owners do that before.
He brought me the rifle and asked if I could possibly help him. I told him there are two ways to go about this. One is to wait a couple months and hope that the gun leaks down enough that the valve is no longer locked. If the gun had not been properly oiled with Crosman Pellgunoil, that might have been a possible solution. But it was well-oiled, and I didn’t think it would leak down in even a year!
I decided to go the other way. I would remove the extra air mechanically by partially disassembling the gun and rapping on the valve stem with a heavier hammer. That’s how the repair center fixes guns that are over-pumped. Or, at least it used to be! This is where the “old plumber” became a student, again.
I discovered that the new 397’s design is vastly different from what I was used to. You can no longer do what I just said because the gun is not designed to allow it. The new design is much cheaper to build and easier to repair — except when the gun is over-pumped. I’ll describe what I did and what happened as a result — and I don’t see any other way of doing the job.
Poor photos today
I apologize for the poor photos that follow. I was working on the gun and getting dirty, so I used the flash on the camera to make the work go faster. That’s why everything is so over-exposed.

What appears to be the stock screw also holds the valve inside the pressure tube. If the rifle is pressurized, this screw will be under pressure from the valve body trying to move! If this is the case, remove the bolt before you loosen this screw!
The new 397 valve is held in the gun by the single stock screw. That screw fastens the trigger group to the action, and there’s no way to rap out the air the way I described it earlier. I did an internet search and discovered there were no instructions on what to do! In fact, everyone dances around this design almost as though they don’t understand it, though I’m quite sure most of them do. It’s so much simpler than the guns I’m used to. When a gun is over-pumped, there seems to be no good way of depressurizing it — other than to remove the single screw I just described and let the air blow out. But before you do, be sure to remove the bolt first!

Remove the two sideplate screws and the sideplate and cocking plate will come off (right and left, respectively in this photo). Then, you can remove the Allen screw from the bolt.

Once the Allen screw is out, the bolt slides out of the receiver.
I didn’t know it while I was doing it, of course, but when the stock screw backed out sufficiently far, the air exploded out of the gun as the valve moved within the pressure tube. It caught me by surprise, but in retrospect I can’t see a better way of doing the job. If anyone knows of one, I’d like to hear what it is.
In retrospect, I should have removed the bolt from the gun before removing the stock bolt. To do that, remove the two screws that hold the sideplate to the left side of the action, exposing the Allen screw on the bolt that cocks the hammer. Then remove the Allen screw, and the bolt slides out of the action.

The action can be removed from the stock when the one Phillips screw is loose. The screw is captive inside the stock and doesn’t show here.
At this point, I finished the disassembly, checked all the parts to see that they were okay, which they were, and assembled the gun again. There’s a trick to assembling this gun. The pump arm must be swung forward to allow the valve to go forward enough for access to the screw hole. If you do that, this is an easy pneumatic to assemble. If you don’t — good luck!

You’re looking through the screw slot in the triggerguard at the brass valve body and its fastening screw hole. How many people would realize that their one stock screw is holding all this?

This picture shows why you cannot just rap out the air anymore. The rear of the pressure tube is blocked by the back of the trigger assembly, which has to be removed to gain access to the valve.
And how does it work?
The rifle now works fine, but I’ll run a little test to see how fine. I’ll shoot the gun through a chronograph on six pumps, and keep increasing the number of pumps until there air remains in the gun after the shot. Then, I can tell the owner what the exact maximum safe number of pumps are for this specific gun. That’s another great reason for owning a chronograph!
Checking the velocity
I decided to use Crosman Premiers in the 7.9-grain weight for my test pellets. This is what the gun now does.
Pumps…Velocity…Air remaining?
6………….613………..No
7………….650………..No
8………….688………..Yes! A soft pop was heard.
9………….713………..Yes — a second shot went 555 f.p.s.
Chronograph reveals what happened
It’s easy to see what happened to this rifle. I told the guy that 10 pumps was the maximum, because I thought that was what the owner’s manual said. But it isn’t! Crosman has folded the Benjamin rifles and Sheridan rifles together, and now they all top out at 8 pumps. So, I was responsible for the owner over-pumping his gun! Several years ago, when the Benjamin and Sheridan brands were different, the Sheridan stopped at 8 pumps but the Benjamins stopped at 10. But those days are over. Now they all stop at 8. So — shame on me! Apparently this is my week for confessing my sins.
What if you don’t own a chronograph?
But you don’t care about that! You care about your own air rifle, and, since you don’t own a chronograph yet, how can you determine the exact number of pumps that are maximum for your rifle? It’s simple. Do what I did above and increase each shot by one pump. Then cock the rifle afterward and fire it again without a pellet. Listen for the pop of escaping air. When you hear it, back off one pump and that is the maximum number of pumps your rifle can handle.
Just to be safe, pump your rifle to the newly established maximum number of shots five times and shoot it. After the fifth shot, cock the gun once more without pumping it and fire it again, listening for a pop. Sometimes the amount of air that remains is so low you cannot hear it, but after a cumulative five shots, you should be able to hear it very well.
Lessons learned
I got the tables turned on me this time. And I also learned how easy it is to work on these new Benjamin rifles. And you readers got to watch everything over my shoulder, plus you got a new way of testing the maximum number of pumps for your specific pump rifles if you don’t own a chronograph. I would call that a good day’s work!
Quackenbush .25 pistol: Part 2
by B.B. Pelletier
Test data and photos by Earl “Mac” McDonald
Nobody played!
First of all, we got no answers on last Friday’s question at the bottom of the blog. The answer is: it’s a catapult gun, and it shoots steel BBs. It was offered by the same company that built the Johnson semiautomatic rifle that was used as an alternative by the Marines in World War II, but at the price of $15 in 1948, it never stood a chance.
Today, we’ll shoot the Quackenbush .25 pistol for velocity and accuracy. There was a surprising amount of interest in this pistol, though much of the talk took place on Pyramyd Air’s social network sites. But even here, many readers know about this airgun. Just as a reminder, this isn’t a fire-breathing PCP. It’s a CO2 gun that uses the same stock valve as a Crosman 2240.
This pistol bloops them out at less than 400 f.p.s. because it’s a .25 and shooting pellets far heavier than the valve was designed to handle. Mac says he loves watching them arc out through the scope and drop through the aim point at the last instant. When the sun is behind you, it can be quite a show.
Velocity
We’ll start with the velocity first. A couple of readers guessed that this pistol would shoot under 400 f.p.s. and they were right. The fastest average velocity Mac recorded came from Diana Magnum pellets — an obsolete brand that used to be the best .25 caliber pellet on the market. Until now, Mac has found that it shot best in this pistol. Although Diana Magnums came in both 20- and 21-grain weights (they varied over time), Mac says these weigh an average 19.90 grains, so these are the lighter ones.
Because this is a CO2 gun, Mac had to allow for cooling — so he waited 15 seconds between each shot. That allows the gun to warm up. He also replaced the CO2 cartridge after 24 shots, even though he says the gun gets up to 40 shots per cartridge. That gave every pellet the best chance to perform.
Mac recorded an average 378 f.p.s. with this pellet. The total spread was 7 f.p.s., which is pretty tight for such an inexpensive airgun . At the average velocity, this pellet generates an average 6.32 foot-pounds of energy at the muzzle. Because this is a gas gun, it’s probably going to get more energy from heavier pellets.
Next up was the Beeman H&N Match wadcutter pellet. Weighing 21.6 grains, they averaged 370 f.p.s., with just a three foot-second spread. The muzzle energy was 6.57 foot-pounds.
Mac upped the ante with one of the two new .25-caliber pellets. The Benjamin dome weighs 27.8 grains, so it’s a heavier pellet in this caliber. It averaged 323 f.p.s. with a 7 f.p.s. total spread. The muzzle energy was 6.44 foot-pounds, so less than you would predict; but because it’s a Benjamin pellet, there’s antimony in the alloy, and that may slow it down just a little.
I told Mac that this pellet and the next one are the two most accurate .25-caliber pellets on the market. I expected both of them to beat the Diana Magnum in his pistol.
The final pellet he tried was the new JSB Exact Kings that weigh 25.4 grains. This is the other very accurate pellet that Mac tested. It averaged 346 f.p.s. and generated an average 6.75 foot-pounds. The total velocity spread was 9 f.p.s.
Okay, now the velocity testing is out of the way, and what do we have? The pistol averages under 400 f.p.s. but over 6 foot-pounds of energy. So, it isn’t a weak air pistol. Slow, perhaps, but not weak. So, how does it shoot?
Accuracy testing
Mac shot the pistol at 25 yards. I asked him to shoot 10-shot groups instead of the five he used to shoot with this gun. That made a difference in the group sizes, of course. But another dynamic emerged during testing that I think you’ll find very interesting. I’ll explain it as we go.

Ten shots at 25 yards. Believe it or not, the first four shots are all strung apart from the main group, where the last six shots went. Group measures 2.16 inches between centers.
Do you see the dynamic? The group forms around the final shots. Mac did “season” the bore between targets with two shots from each new pellet; but, even so, the pellets walked into the group at the end of each 10-shot string. I suggested to Mac that this might be due to seasoning the barrel, but he thought it was because the gun cooling down as it was shot.
The heavy JSB Exact Kings were next up. Mac found them to also string vertically for the first three shots, then bunch together at the end, just like before.

Ten JSB Exact King domed pellets made this 1.09-inch group at 25 yards. The first three shots are vertical, then the final seven are bunched together below. There’s one straggler out to the right, but this is a much better group than the wadcutters produced.
Thus far we have seen an interesting dynamic of the pellets moving to a place, then grouping tightly. So how do the formerly most accurate Diana Magnums react? They’re next.

The Diana Magnum pellets didn’t act like the first two pellets. They all landed at the same height on target, without an vertical stringing. Group size was 1.09 inches between centers.
The Diana Magnums don’t seem to follow the same pattern as the first two pellets. I don’t know why that would be, but that’s what the target shows. As with all other pellets, Mac seasoned the bore with two shots before this group was fired. Let’s go to the final pellet and see what happens.

The Benjamin domes gave the smallest group of ten shots at 25 yards. Group measures 0.85 inches between centers. Again, we see a vertical orientation to the group; though, this time, Mac didn’t indicate that the final shots were all bunched together in the large hole.
The results
There you have it. That’s what this Quackenbush .25 can do.
In my opinion, Mac should pick just one pellet — the Benjamin dome — and shoot nothing else in this gun. I think the tighter groups at the end are due to seasoning the bore; because in my other testing, I’m starting to see very similar results. But even if that isn’t what’s happening here, the Benjamin dome is still the accuracy champ.
Is the Quackenbush conversion a good thing for a Crosman 2240? If you want a .25-caliber air pistol and you don’t want to get into high-pressure air, then I guess it is. You must accept the low velocity, while realizing that this pistol is still a good deal more powerful than a Beeman P1. And because it’s launching very heavy pellets, it retains more of that energy longer downrange, so things keep getting better the farther the target is from the muzzle — within reason.
This much is certain — people love tinkering with their Crosman airguns, and Dennis Quackenbush has provided the means to do that for over a decade and a half. This may not be the only game in town, but it’s certainly one of the very best.

The Quackenbush .25-caliber conversion is a neat way to customize your Crosman 2240.









