Hopefully someone can help me out...
Does anyone know if bolt head rollers are surface hardened or through-hardened? Reason I ask, my brother has a CA 89 that is a PDW clone. It is an sbr. I'm in the process of transferring it to me. I've done a lot of work to this gun in the past to get it running. I have a suppressor and want to run it on this gun. It came with a HK number 16 LP in it. I put a RCM number 28 in it, but the bolt gap shot up to .039 with the standard 8mm rollers.
I can't get proper bolt gap with even -8 rollers that are available. A German 28 lp seems to be impossible to find and ridiculously expensive even if i were to locate one. I made a set of rollers (just to try) from some scrap stainless that I have on-hand. Turned them down to .3075 and got .017 bolt gap. Gun ran like a champ and suppressed well. My try-rollers aren't hardened and definitely won't last any amount of time.
If the rollers are through-hardened, I can grind them with a tool post grinder to the dimension needed. If only surface hardened, I'll have to make my own, and harden them. Just trying to find out before I jump in, and have to do twice the work.