you should try a search on this - there's some of the exact same questions addressed. but basically I had the same problems when I dropped my buffer in. I trimed it down with an exacto knife - cut about 1/4 of it away and tried to sand out the unevenness. jams disappeared, but the bolt would still close on an empty clip which made for unecessary dry fires (I wasn't used to counting rounds, just looking for the open bolt). So, I threw the thing out. folks on this forum say though that after a "break-in" period the buffers are supposed to work a little better. I do recall it helped a little, but not som much so that I couldn't live without it.