Making Homemade Barrel Adapters

What does a handgun hunter who is using a Thompson-Center Contender in a large pistol caliber do when presented a target that would be destroyed by that large load? There usually isn’t time to install the .22 barrel that would do a better job, so the camp meat makes a clean getaway. What that hunter needs is a .22 LR or .22 Magnum insert barrel.

Next question: What does a gunsmith do with all the .22 barrels and stubs he has put up in the “good junk” box in his shop? If there is less than 16 inches of usable material, probably not much, aside from making an occasional fixture, shim, or tent peg.

The answer to both questions sits collecting dust in your iron pile. Since that Contender has an interchangeable firing pin, an insert turned out in the cartridge-body size with an overall length of 5 or 6 inches (or even 10 if you like), and chambered for the rimfire of your choice does the trick. These inserts make a handy second barrel and, depending on the length, are quite easily packed into the field. The sights are set up for the larger caliber, so using the old Kentucky windage system or making a sight adjustment to compensate for the smaller caliber will be in order.

I have made these adapters for .45 Long Colt, .44 Magnum, .357 Magnum, .38 Special, and .30/30 Win. These are the barrels I have—or have had—for my first-generation Contender. I fell heir to a number of M16/AR15 barrel ends that were cut off just behind the handguard cap/front-sight shoulder, and though they were .223 bore diameter, they worked quite well with long-rifle ammunition at .218. The WRM ammunition, being larger, did a bang-up job through these barrels.

Cutting and facing off these stubs at the gas port gave me a barrel of 63/4 inches from end to end. Turning them down between centers will keep the free bore area (from the end of the adapter to the end of a 10-inch barrel) out of danger of a skidding .22 slug. Of course, a 10-inch adapter would be best, but I was using up what I had on hand at the time.

The extractor lifts the adapter out as it would a fired case of the barrel’s caliber. A section of drill rod will knock out a .22 case from a well-prepared adapter chamber. I made a punch out of a section of aluminum cleaning rod turned down on one end to fit into the fired case. Bump it on a hard surface and the case is out.

Of course, this system may seem a bit rudimentary by contemporary standards, but it works well and can save the cost of a complete .22-caliber replacement barrel in these times of tight money. It might even turn a dollar out of what otherwise might be tubular junk!

A Remington 40X barrel, unusable in its original length because it was bent, made an especially good 10-inch adapter for a .44 Magnum barrel. Its owner used the adapter for low-noise, off-season practice with his Contender. The Remington barrel was built as a target item, but almost any modern .22 rifle barrel that isn’t washed out will work well.

Although not as inherently accurate as the longer barrels, adapters made to the dimensions of the Contender chamber, plus an inch or two projecting into the bore, are suitable for plinking, and greater numbers of them can be carried at one time. This system was used by Smith & Wesson a number of years ago in its short-lived .22 Jet revolver.

For the one-caliber Contender owner or the handgun hunter who doesn’t want to carry that second barrel, the .22 barrel adapter may be just what is needed. For the gunsmith, it’s a good “slack time” project that can help turn trash into treasure.