making a shotgun chamber adapter from a chopped .22LR barrel

A

AManWithAGun

Regular
Rating - 100%
36   0   0
Location
BC
Hi,

Has anyone tried this at home ?

I cut 6 inches off a .22LR barrel (the adapter) and thought: "Why not make a chamber adapter from it for my single-shot shotgun ?" I know to fire rimfire rounds, the firing pin must crush the rim, and it'd be difficult to make the adapter fit tightly off-center inside the shotgun barrel. But I put a spent .22LR case centered against my shotgun firing pin and pulled the trigger. The firing pin made a big rim-to-rim dent in the base of the .22LR case, and I thought maybe that's enough to fire it.

So I filed the adapter down and made it fit tightly and centered inside the shotgun barrel. Next I drilled out a "chamber" at the end of the adapter, and enlarged the opening for the rim so .22LR rounds can fit in comfortably.

I loaded a CB round and pulled the trigger, again the firing pin made a big rim-to-rim dent in the base of the .22LR round, but it was not enough to crush the rim and make it go bang. I think I have 4 options now to make it work:

1. File down the adapter so it fit off-center in the shotgun barrel, and use some wedge stuff to hold it tight inside the shotgun barrel. But this requires a lot of filing effort.

2.Build a contraption to attach the adapter to the shotgun without using the shotgun barrel. But I think it would not be a chamber adapter any more, I would have made a prohibited rifle with a 6-inch barrel.

3. File down the adapter so it sinks a little more into the shotgun barrel. Then take a small, hard metal plate (maybe a penny) and make a sharp dimple off-center. Put this metal plate against the adapter. The firing pin strikes the center of the metal plate, and hopefully enough energy is transfered thru the dimple and crush the .22LR rim and make it go bang.

4. Make an off-center firing pin.

I think #4 is the easiest to do, but I have to disassemble the shotgun to switch between .22LR and shotgun ammo. #3 is far more user-friendly, but feels kind of iffy.

Any other ideas ? Any suggestion would be greatly appreciated.
 
I'd say that you should have shaped the offcut so that the stock firing pin struck just the edge of the rimfire more forcefully with a smaller contact area so that it generated the proper impact to set off a rimfire cartridge. Of course this means a seriously off center bore but c'est la vie and all that.
 
while I see a number of problems with the technique that you are describing, you could address the firing pin issue with a floating pin and seating the 22 shell 3/8" further into the adaptor barrel. I would use a blade rather than a point on the floating pin, so that it strikes the whole end of the shell. If that does not work then file out the center of the blade so that it strikes at 12 oclock and 6 oclock and does not use up energy in the middle

cheers mooncoon
 
Numirch sells them for like $20 .22lr, 9mm, 357mag.

Why even bother, a smooth bore barrel loaded with your choice of bird/buck shot is very versatile, covers everything from .22 to 9mm easily. Rifled/cast slugs are far better than any .357mag load.
 
If you succeed in making a rim fire adapter go bang, I doubt you will ever hit anything you aim at.
 
577/450 said:
Are they prohib? I just bought a couple of adapters from a company in the US and they came over by mail no problem.
Click to expand...

The adapters are not....but taking a hack saw to a barrel and making a "barrel" of less than 18" is. I KNOW THAT IT MAKES NO SENSE.
 
Prohibited barrels refer to handgun barrels and do not need to include chambers. Think for example of a revolver barrel.
As applies to a chamber adapter, it is not designed to be used in conjunction with a frame only but rather inserted into an existing (normally legal) barrel. If the chamber adapter was fastened onto a rifle/shotgun frame only it would create an illegally short barreled gun but inserted into a legally barreled gun I think it only becomes an adapter and since it is not designed to be used installed in a handgun frame, it should not be a prohibited device

cheers mooncoon
 
mooncoon said:
Prohibited barrels refer to handgun barrels and do not need to include chambers. Think for example of a revolver barrel.
As applies to a chamber adapter, it is not designed to be used in conjunction with a frame only but rather inserted into an existing (normally legal) barrel. If the chamber adapter was fastened onto a rifle/shotgun frame only it would create an illegally short barreled gun but inserted into a legally barreled gun I think it only becomes an adapter and since it is not designed to be used installed in a handgun frame, it should not be a prohibited device

cheers mooncoon
Click to expand...

So, by your logic it's ok to cut down a shotgun barrel to any length you please?
 
I agree with mooncoon's interpretation. the barrel is not by itself prohibited unless it is attached to a frame. Stick it in the shotgun chamber as a .22 adapter and it is just part of the longer shotgun barrel, which is still non-restricted as it was not shortened.

It certainly would be a problem if you put it back on the original .22 frame in it's shortened condition.
 
TBMH said:
So, by your logic it's ok to cut down a shotgun barrel to any length you please?
Click to expand...

Nice leap of so called logic.

The subject at hand is a chamber adapter to be used inside an existing, legal firearm barrel, that cannot be used elsewhere. As in, not a short barrel, but a section of barrel stock made to only work inside and existing barrel. Not a handgun barrel, and not a illegal short barrel.

My vote is with the "you won't hit anything you aim at" crowd.

Probably the only rimfire insert that I know of that is reasonably accurate is the Crosno one for the larger target guns of old. Guys report that they shoot very well. They use a longish barrel, centered by fairly tight fitting O rings. I think that is a design worth stealing. Make what is effectively a large extended cartridge and set it up so the bore is centered. Take a look at the link for cartridge adapters that was posted a few days back. Many of them use a firing pin adapter that fits in behind the cartridge. It wouldn't be too tough to make such as would transfer the strike of the centerfire pin to the rimfire cartridge. You would have to keep track of all the parts and carry a small rod to poke the cases out with, though.

Cheers
Trev
 
trevj said:
My vote is with the "you won't hit anything you aim at" crowd.

Probably the only rimfire insert that I know of that is reasonably accurate is the Crosno one for the larger target guns of old...
Click to expand...

What is reasonably accurate here ?

I'm not expecting good accuracy. If I can get accuracy of a cheap handgun with a 6-inch barrel, I'd consider it a success. Yes the adapter is not a good barrel and probably doesn't fit inside shotgun barrel tightly enough for accurate shooting, but I hope that would be offset by the longer sight radius and heavier gun and shooting like a rifle.
 
TBMH said:
So, by your logic it's ok to cut down a shotgun barrel to any length you please?
Click to expand...

A short handgun barrel is a prohibited device.
A shotgun - or other longarm with the barrel cut below the legal minimum is a prohibited firearm. But a cut barrel is not a prohibited device; that only applies if it is a handgun barrel.
This has nothing to do with adapters that fit inside another barrel, regardless of length or caliber.
A piece of barrel under 105mm is not a prohibited device unless it is a handgun barrel.
 
You must log in or register to reply here.
Back
Top Bottom