by B.B. Pelletier

Part 1

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.

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.