Quackenbush .25 pistol: Part 2

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.

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.


Quackenbush .25 pistol: Part 1

by B.B. Pelletier

Test data and photos by Earl “Mac” McDonald

Back in the 1990s, Dennis Quackenbush made a nice part of his living by modifying single-shot pistols from Crosman. In those days, there weren’t as many places to buy aftermarket parts, and Crosman didn’t have a custom shop. In fact, when Dennis and I were seated with Crosman’s CEO at an NRA Airgun Breakfast at the 2001 NRA Annual Meetings and Exhibits in Kansas City, Missouri, we introduced ourselves and he asked both of us what we did. Dennis told him that he made his living modifying Crosman single-shot pistols. “You sell them (the SSP 250) for $39 and I modify them for $125. I can’t keep up with all the work!”

To say the man was stunned is an understatement. I don’t think he believed Dennis, because he restated what Dennis had said, “You mean people pay you $125 to modify a gun that sells for $39?” You could hear the disbelief in his voice.

That man didn’t remain at the reins much longer. And his replacement, Ken D’Arcy, instituted the Crosman Custom Shop a few years after he stepped in. But that did not diminish the number of aftermarket places that modify Crosman airguns and make parts for owners to install. If anything, the number of places increased, though I would not say that it was in response to the Crosman Custom Shop starting up. But it was and still is a direct result of the openness of the Crosman Corporation toward their customers, by providing parts and information that support their guns.

For several years, one of the most popular modifications Dennis made was a steel breech for the Crosman 2240 single-shot pistol. Not only is it stronger and more rigid, it also allows for the installation of a scope — something that most home tinkerers will want to do. And Dennis switched the bolt handle to the left side for right-handed shooters, because they want to continue to hold onto the pistol while they load it. People who don’t shoot these pistols don’t understand that desire, but it only take 15 minutes with one and you understand completely. That one change may have been his greatest contribution, because it showed everyone what a little thought can do to enhance the operation of an inexpensive airgun!

Many of the handguns Dennis built on Crosman frames are righteous thumpers, with power levels far beyond anything Crosman ever envisioned. Dennis has made several guns on this 2240 frame that achieved 100 foot-pounds of energy at the muzzle, and I’ve personally witnessed one that produced 300 foot-pounds. So, like the modern AR, there’s no limit to what you can do with one of these flexible air pistols.

But in this report, we’re going to look at something a little closer to the original gun. It’s a .25-caliber pistol that has the steel receiver from Dennis and a 10.5-inch barrel that he rifled. In terms of power, it’s been left pretty close to original; so it gets a decent number of shots. Because of the large caliber, they don’t go very fast.


The Quackenbush .25-caliber pistol is built on a 2240 frame. It has a steel receiver, and the bolt is on the left side for easier loading.

There are no open sights, as Dennis envisioned owners would want to scope the gun. The receiver has an 11mm dovetail cut into the top. Since the frame is from a 2240, it readily accepts an add-on carbine stock that so many shooters seem to prefer. Certainly, when you put a heavy rifle scope on the pistol, the stock is the best way to go!

Mac reports that the pull length with the carbine stock is 16.3 inches, but the angle of the grip makes it feel shorter. He says it fits him well, and he usually likes a rifle with a pull length of 13 inches. I looked at the pictures he sent and see that the scope hangs back behind the receiver on this gun. That may be why the long pull doesn’t feel so bad. Also, the gun is very light, at only 48 oz. in the scoped pistol configuration, so there’s not a lot of weight hanging out front. The shoulder stock adds another 13 oz.


The optional shoulder stock is something nearly all pistol owners have.

Dennis didn’t number all of the guns that he made, but partway through the production he began to put his own serial numbers on them. His last gun carried the number 850. Mac’s pistol is numbered 509.

Though Dennis no longer makes complete guns, according to his website he still does make the parts for them so owners can modify their own guns. The velocity of the .25-caliber pistol is approximately the same as the 2240 that it was modified from when shooting a 14.7-grain .22-caliber pellet.

The features of this modification are:
Steel barrel, receiver and bolt
The barrel is threaded into the receiver
The transfer port is in the breech instead of the barrel
The new steel bolt is larger than the pellet
The bolt contacts the pellet’s skirt — no probe is used

The pistol is 14 inches long without the shoulder stock, and 26 inches in the carbine configuration. The trigger-pull is a repeatable 43 oz., though some may find the trigger blade a bit too thin for comfort. The scope you see here is a cheap Simmons that Mac thinks was probably a rimfire scope at one time. It has a one-inch tube and fixed 4x magnification. The 32mm objective lens has a fixed parallax that Mac adjusted to 25 yards by turning the lens locking ring.

While many .25-caliber single-shots produce lots of muzzle energy, this isn’t one of them. Those guns are modified into PCPs, where this one is still a CO2 gun. It gives you a taste of a larger caliber without all the extra fuss and noise that a magnum blaster would have.

Mac tells me this pistol is quite accurate, and he loves the way it lobs them in. Next time, we’ll combine Parts 2 and 3 for a good look at the performance of this vintage Quackenbush airgun.


With the longer barrel and no open sights, this pistol looks slicker than the 2240 it was modified from.