Much has been stated here about the questionable quality of the Bolts and carriers floating around from various suppliers. I have a Bushmaster Dissipator upper w/ BM bolt that I am sending to Adco for some work. Do I have an “acceptable” bolt already? Should I upgrade the bolt to LMT or other (suggested)? Just the bolt or the carrier as well? If I get a new bolt now, Adco can check the headspace while doing the other work.
TIA,
Mike
It depends…the first BM I got was from 1999 and 1) short-stroked due to loose carrier key, 2) windage was way off due to improper indexing, and 3) had a CAST bolt due to short Y2K parts supply shortages (I’m guessing). I haven’t had an issue with the cast bolt yet, but the carrier doesn’t protect the firing pin…I plan to replace the whole bolt carrier group with a BCM or RRA unit at some point. I know the bolt is cast because of the natural shallow “pits” in the surface…I’ve yet to see another bolt like it, BM or not. It’s the worst representation of a bolt I’ve ever seen, but after 2000 rounds or so it’s never failed (after BM replaced the bolt carrier key to solve the short-stroking issue).
If you have a later-model BM with shrouded-firing-pin bolt carrier and decent bolt, I wouldn’t replace anything before it broke. But always keep spares onhand…even for a Colt - stock up on extra parts for large FCG Colts.
My upper, including BCG, is from 2002. It is not porous at all. I suspect that it is not a casting. Maybe I will let it fly.
Thanks for the response.
As long as it is not giving you any issues I’d just keep shooting it.
Replace worn parts as needed.