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

Crosman 2240 conversion to air: Part 1
Crosman 2240 conversion to air: Part 2
R.A.I. Adjustable AR Adapter for Crosman 2240 pistols: Part 1
R.A.I. Adjustable AR Adapter for Crosman 2240 pistols: Part 2

WARNING: This conversion changes the operation of the pistol to use air at up to three times the pressure it was designed for. The parts that are installed are strong, but there are other parts in the gun that aren’t changed and could fail when subjected to the higher pressures. Pyramyd Air advises against making such a conversion. This report is for information, only.

Crosman 2240 air conversion long barrel
The steel breech and longer barrel increase the 2240’s length dramatically.

This report covers:

• Installation of a steel breech and longer barrel
• Easy steps
• First velocity test
• Crosman Premier pellets
• RWS Hobby pellets
• RWS Superdome pellets
• What have we learned?
• Replace the striker spring with a heavier spring
• Crosman Premier pellets
• RWS Hobby pellets
• RWS Superdome pellets
• Evaluation to this point

This is the third look at converting a Crosman 2240 CO2 pistol to run on high-pressure air. In the last report, we saw how the conversion works with the factory barrel and factory striker spring. Today I will install a longer barrel with a steel breech and see what that does. Then I will add a stronger striker spring and see what that does.

Installation of a steel breech and longer barrel
Installing a Crosman steel breech and a Crosman 14.50-inch barrel on the 2240 pistol took all of 10 minutes. Four screws were removed, and both the plastic breech and barrel came off. After the detailed disassembly you saw in Part 1 of this report, this modification was a walk in the park.

Easy steps
The new breech was made by Crosman and sold by Pyramyd Air for $38, plus shipping. The barrel was also made by Crosman, and I bought it off eBay for $37 plus shipping. Together, these two parts have added about $85 to the cost of the gun, on top of the $65 for the air conversion that was given to me by Rick Eutsler. That’s an additional $150 I’ve put into this gun. And I’m not counting the adjustable stock and adapter that turns this pistol into a carbine. I’m not complaining about the cost, but don’t let anyone say this is a cheaper route than buying a Benjamin Discovery outright. What you get with this conversion is the time you need to make the investment. You can do this in easy steps.

First velocity test
I left the factory striker spring in place for this first test and pressurized the pistol to 2000 psi. Then, I shot the same 3 pellets I’ve been testing all along:

14.3-grain Crosman Premier pellets
11.9-grain RWS Hobby pellets
14.5-grain RWS Superdome pellets

Below are the velocities on CO2 for the factory gun; then the velocities for the factory gun with the high-pressure air conversion; and finally the velocities for the gun with the steel breech, longer barrel and factory spring — all operating at 2000 psi.

Crosman Premier pellets
CO2 avg…………..Air in factory gun average…………..Air in long barrel average
448 f.p.s…………………..486 f.p.s………………………………………517 f.p.s.

I got 15 shots with this pellet and the longer barrel. They ranged from 504 f.p.s. to 524 f.p.s.

RWS Hobby pellets
CO2 avg…………..Air in factory gun average…………..Air in long barrel average
482 f.p.s…………………..526 f.p.s………………………………………564 f.p.s.

This pellet gave me 18 shots from a 2000 psi fill with the longer barrel. They ranged from a low of 548 f.p.s. to a high of 573 f.p.s.

RWS Superdome pellets
CO2 avg…………..Air in factory gun average…………..Air in long barrel average
455 f.p.s…………………..483 f.p.s………………………………………525 f.p.s.

Superdomes gave 14 shots on a 2000 psi fill. With the longer barrel, the low was 516 f.p.s. and the high was 534 f.p.s.

What have we learned?
Obviously, the pistol shoots faster with the longer barrel and no other changes. Adding the steel breech does strengthen the rear of the barrel, but it doesn’t add anything to velocity.

All 3 shot strings posted above started out slow and increased as the shots were fired. So, the pressure curve is about ideal when the fill is at 2000 psi.

The velocity increase from CO2 in the standard pistol to high-pressure air in the longer barrel is very significant. But by leaving the factory striker (hammer) spring in the gun, we’re not getting all this conversion has to offer.

Replace the striker spring with a heavier spring
The kit Rick Eutsler sent me contained two striker springs — both of which are stronger than the factory spring. I removed the factory spring and installed the spring that was the weakest of the two, though stronger than the factory spring. I wanted to keep the fill pressure at 2000 psi, and the strongest spring would not be the way to do that.

I filled the gun to 2000 psi and proceeded to shoot Crosman Premiers. Here are the first 8 shots.

581
577
576
575
578
576
570
568

The velocity dropped with almost every shot. Yes, there are a few exceptions, but the trend is generally down. What this means is that the new spring is too strong for the fill pressure of 2000 psi. The pistol wants to start at a higher pressure with this spring.

I decided to fill the gun to 2250 psi. This is above the maximum I wanted to use, but it illustrates the relationship I just mentioned and is worth a look. Let’s look at the velocities at this pressure.

Crosman Premier pellets
588 f.p.s. average, low 582 f.p.s., high 594 f.p.s.

Compare the above to the average velocity with the factory striker spring and longer barrel, which was 517 f.p.s. This is a huge increase of 71 f.p.s. The stronger striker spring gives more of a boost than the longer barrel by itself. But — and understand this — without the longer barrel, the stronger spring would only waste more air. This is a modification that requires all the components to work together. You can’t just pick one item and be done with it.

RWS Hobby pellets
640 f.p.s. average, 632 f.p.s. low, 646 f.p.s. high

The remarks are the same for Hobbys as they are for the Premiers.

RWS Superdome pellets
590 f.p.s. average, 580 f.p.s. low, 596 f.p.s. high

Same remarks apply to this pellet as to the others.

All three pellets gave me maximum shot strings of 10 shots when set up this way. Obviously, more air is being used and the volume of the reservoir has remained the same.

Evaluation to this point
We’ve taken this Crosman 2240 pistol from one power on CO2 to a much higher power with high-pressure air, a longer barrel, a stronger spring and a steel breech. These modifications cost a total of $150 over the cost of the initial pistol ($60). Is it worth it?

The answer will depend on who’s talking. Some shooters enjoy putting their hands on the parts of their airguns and making their own creations. Others look at the total investment and just want something that shoots well for the least amount of money. This 2240 modification is not for the latter group, because we still have to add a $60 RAI adapter and a $60 UTG Adjustable Stock. That brings the cost of the gun we’re modifying to a total of $330.

The next step is to try this modification for accuracy. For that, I’ll attach the adapter and stock, again. I think it has to be tested to at least 25 yards with a scoped gun.

WARNING: This conversion changes the operation of the pistol to use air at up to three times the pressure it was designed for. The parts that are installed are strong, but there are other parts in the gun that aren’t changed and could fail when subjected to the higher pressures. Pyramyd Air advises against making such a conversion. This report is for information, only.