M1 Carbine help

[willp58]

Hello,
I have an M1 Carbine that jams about every 5-6th shot on the empty.
The empty doesn't throw out cleanly and ends up sideways in the reciever..
So far I've replaced the Operating slide spring and the Ejector spring and the Extractor spring.
It's hard to tell exactly but it appears that the bolt is not traveling rearward quite enough because on the jams, the bolt is not cocked.
Could this be the piston? The rest of the weapon looks in perfect condition.
Any suggestions will be appreciated...
Thanks, willp

 

[4 eyed six shooter]

It does sound like it's a short cycle problem. Have you cleaned out the gas port, cylinder and piston? If the port is carboned up, it can cause the problem that you are experiencing, also check the gas piston and cylinder for gumming up due to excessive lubrication that may have burned onto these parts . Other than that it could be less than full power ammo, worn gas cylinder/piston, something rubbing or improper lubrication.
Give it a good cleaning and inspection and try it again.
Good luck, John k

 

[Pistolsmith]

When Marsh WIlliams was working on the prototype carbine at Winchester, he experienced the same problem, which proved to be an underswized access hole to the piston head from the bore. He set the barrel up in a drill press and promptly broke it off, making removal a major operation.
When I had this problem (in the Ordnance Corps) I chucked the proper diameter of new hss twist drill in a pin vise and carefully turned it from the housing to the bore. Do not attempt to enlarge the hole, just clean out the accumulated carbon.
Thereafter, do not put oil in the barrel; use Rig or other gun grease and follow it with a dry patch.
Never, ever, try to open the hole with the drill bit powered by a drill press or hand drill. Turn it by hand in a pin vise and use a good solvent, clearing the flutes every few seconds; carbon deposit in this hole can become as hard as steel.
Some powders are less inclined to gum up the works.

 

[willp58]

Thanks for the info on this! I'll give this a try and post what happens..

Again, thanks, I appreciate the help.

Willp