My thoughts,although controversial - - -> SOFT lead going past any gas ports shaves off some lead. But I feel what is worse is the bullets lube that is put thru the gas system. Most of the lube used is somewhat waxy or gummy. Especially if it is at a high temp.
While it may or may not . . . ummmmmm . . . "hurt anything",I say,why do it. Jacketed bullets are cheap. Especially the milspec "pulls".
Get a buddy or two and share them. Buy the 55gr FMJ M193 type (or others) in large quanities. They are cheaper than any lead bullet.
Lastly,if you just gotta use lead,use hard lead. --- SAWMAN