I found this on the ultimax website http://www.ultimak.com/default.htm and i am wondering if anyone has had problems shooting cast bullets in their m1 carbine. I am not sure how many hundreds of cast bullets i have shot with my m1 carbine but i have not noticed any problems.
The website: http://www.ultimak.com/M6instructions.htm contains the following.
Tip: Never use bare lead bullets in your Carbine. Though they may feed and function for a while, each lead bullet will leave a tiny shaving of lead in the gas channel. Eventually, the gas piston will jam on the lead shavings, rendering your Carbine inoperable. The only cure is to completely strip the Carbine, remove the piston, and clean out all the lead. It can be dangerous too: Since the jammed piston will not allow the op rod all the way forward, it could result in a cartridge firing "out of battery" (firing with the bolt lock lugs only partially engaged with the receiver). Use only jacketed bullets, as the Carbine was designed for them. JPHs (jacketed hollow points) will be fine as long as they feed reliably and leave no lead exposed to the bore surfaces.
Elfego