M1 Carbine barrel replacement

[CoalTrain49]

I have an M1 carbine that needs a new barrel. Will I have to replace the bolt or can the new barrel head space be machined to accommodate the existing bolt? Also can the front sight be removed from the old barrel and used on the new one. Thanks.

 

[Kp321]

Depends. Some new, old stock barrels are short chambered and will need to be finish reamed. Used barrels will usually be OK. There was a long discussion on this forum recently on Carbine headspace. The consensus was if the bolt closes on a sized case and it will fire, you are good to go. Since the round headspaces on the case mouth extreme excess headspace would lead to light primer strikes but anything tighter than that is OK for the moderate pressure, straight cased cartridge. Not ideal, but safe.
The front sight can be transferred to the replacement barrel.

 

[carbine85]

In my experience most of the military barrels will head space. Winchester barrels where short chambered and required reaming. I can't say what a commercial barrel will be. You need to make sure the lugs on the bolt and the receiver are still good and not worn down. You don't correct the head space by machining the bolt or receiver. IMHO you need the gauges and check it. The "if the bolt closes it's ok" thing doesn't get it with me.

 

[rondog]

straight cased cartridge

They're not straight, actually very slightly tapered. Try resizing one with no lube!

 

[Jim K]

The carbine barrel is very critical for proper alignment (clocking) . If it is off even a little, the gun will malfunction or shed the slide.

Jim