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

This report addresses:

• Missing Part 3 of the adapter report on the Marauder pistol.
• Description of the 2240 adapter.
• Mounting the 2240 adapter.
• Adapter mounted — now what?
• How difficult is the adapter to install?

If you’ve been waiting for Part 3 of the report on the R.A.I. AR Adjustable Stock Adapter used on the Benjamin Marauder pistol, you’ve been waiting a long time. I tested the pistol at 50 yards for a Part 3 report, but the results I got were unsatisfactory. I didn’t think they represented what the pistol can do, so I didn’t report them — and now a lot of time has passed.

I still plan on writing that report when I get a good day at the range, but today I have something different to show you. R.A.I. stands for R. Arms Innovations, an Illinois-based company that makes adapters to connect adjustable AR stocks to various Crosman pistols and turning them into carbines.

Dave Rensing, the owner of R. Arms Innovations, got started by making an adapter so his young son and daughter could shoulder his Benjamin Marauder pistol. When he discovered that the adjustable AR stock makes it possible for the pistol to fit both young people and adults, alike, he knew he was onto something.

Crosman already makes a stock that converts many of their pistols into carbines. But the stock they make has a fixed length of pull. Either it fits or it doesn’t.

The innovative way Dave designed his adapter allows it to be adjusted for a variety of cast-off and cast-on (butt slanted toward the body or away from it) positions, cant angles plus a wide range of comb heights. In other words — a stock that can be easily adapted to fit most people.

This is all just old news for those who read the first 2 tests of the R.A.I. adapter and the Benjamin Marauder pistol. But, today, we’re looking at a different adapter — one that works with the popular Crosman 2240 CO2 pistol. This adapter will be more popular than the Marauder pistol adapter because there are many times more shooters who shoot and modify the inexpensive 2240 family of air pistols.

2240 adapter
The 2240 adapter is very similar to the Marauder adapter, except for the way it interfaces with the pistol. The Marauder has a threaded hole where the power is adjusted. The adapter can bolt directly to that. The 2240 doesn’t have a hole, and the 2240 end cap is flush with the pistol. The adapter for the 2240 had to include a new end cap into which the adapter can be bolted.

RAI adapter bolt
The Marauder pistol has a threaded hole in its end cap to accept the R.A.I. adapter bolt. The 2240 pistol end cap doesn’t have that threaded hole.

Mounting the adapter
To install this new end cap, the pistol’s end cap must first be removed. The rear sight screw and a screw at the top rear of the grip frame hold the 2240 end cap in place. You only need to remove these 2 screws and then the factory cap comes out of the pistol. Next, attach the new cap that comes in the R.A.I. kit. It has a threaded hole that you’ll need. The adapter will then attach to the gun like it should.

Crosman 2240 end cap
Crosman 2240 end cap (right) has been removed and the R.A.I. adapter end cap (left) is ready to be installed. Only two screws are removed for this. The R.A.I. end cap has the threaded hole that accepts the adapter bolt.

Once the adapter is attached, you can screw the buffer tube of any AR extendable stock to the other end of the adapter. I used the UTG 6-position Mil-Spec AR stock on the Marauder pistol, and I note that R.A.I. offers the same stock with some of their kits. Obviously, this is a high-quality stock at a good price.

RAI adapter mounted up
The R.A.I. adapter is mounted and swung up as high as it will go.

RAI adapter mounted down
The R.A.I. adapter is swung down as low as it will go. This lowers the butt considerably. And the adapter can be locked in position at any point around a complete circle.

stock extended
The UTG stock is attached to the adapter and extended as far as it will go.

Stock collapsed
The UTG stock is collapsed as far as it will go.

Now what?
Once the adapter is mounted and the stock is attached, what can you do? This is where Crosman 2240 owners can go nuts because the possibilities are virtually endless. You can use the gun just as it is, like I’m showing here. Crosman puts a peep sight on the 2240; but until you have a shoulder stock, you can’t use it. With the stock attached, I can switch the rear sight to the peep and use it.

But most 2240 owners will probably want to switch to a steel breech. It adds strength to the gun, plus there’s an 11mm dovetail rail on top for mounting scope rings. And that extra strength can be used to hold an 18-inch barrel! Now, you have a carbine that the stock is ideally suited for! Crosman sells all these parts very reasonably.

How hard is it to install?
I don’t like things that are difficult, so I worry when there are parts to be disassembled. But here is what it took to install this adapter. It took a total of 10 minutes for me to disassemble the 2240 and install the adapter and stock. That includes the time spent taking the pictures. It isn’t difficult at all!

In the next report, I get to do something I’ve wanted to do for years. I get to shoot this 2240 using the peep sight!