How does a ".223 to .22lr adapter" work?

simonrichter

New member
I've seen some pics of Kind of "chamber sleeves" on the internet, still I wonder how it is possible to ignite a rimfire .22 with a centerfire .223 striker...?
 
The whole assembly includes more than the chamber sleeve. It also has a bolt assembly which replaces the center fire bolt carrier group. The sleeve you referred to goes into the 223 chamber to create a 22lr chamber with a very, very long throat. The back half of the adaptor is the Rimfire bolt group which performs the extracting, ejecting, feeding and firing functions.
 
How does it work? Like crap in my opinion, I bought one for my single shot H&R rifle and mine works pretty simply, but accuracy is less than stellar. My chamber adapter looks just like a .223 case made of steel, and has a plug for the back that has a rimfire firing pin milled onto it. You drop the .22 rimfire cartridge in the adaptor, put the plug in, close the action, and when the firing pin strikes the plug it has enough force to ignite the rimfire primer.

Here is where I realized it's a waste of time to use a rimfire adapter. I had to extract the chamber adapter every time to use a dowel, section of cleaning rod, ice pick, or small screw driver to push the fired cartridge out of the adapter. Plus my accuracy was never better than about 6" at 25 yards with any .22 LR I tried in my rifle.

The accuracy problem comes from the fact I don't think that .22 LR has the power to obturate (deform) the base of the bullet to make good contact with the rifling. A .22 centerfire rifle uses a bore diameter of .224 and a .22 LR uses a bore of .223 or slightly smaller. While .001 doesn't seem like a whole lot, there isn't a whole lot of force behind those bullets to push the base out to contact the rifling.
 
One time when I was the National Guard years ago we qualified some troops using 22 adaptors in our M-16s, we got pretty good accuracy. I wonder if perhaps an adaptor using 22 Magnums would work better ?
 
The one I bought for my AR works pretty well.
It is a CMMG unit, with a drop-in "bolt carrier" assembly that replaces the original. Do a google search for pics. I have seen at least one other manufacturer who makes them.

I think mine came with three mags for about $200 (although you can buy the kit with one mag for closer to $100, IIRC) and I've only used one mag so far.
Mine works with any .22LR ammo I have fed it so far (CCI Blazer, Federal Classic, Remington Thunderbolt and Federal Bulk Pack).

The only thing that would make me happier would be to find some .22LR ammo to shoot it more. :)
 
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