New to M4C

[sevenhelmet]

Welcome. I'm not an expert like some on the forum, but you could call YHM and ask. If you cannot get an answer you could repost this in the AR Discussion area where more of the sharpies hang out. Looks to me like a good carrier, the staking looks very good and the gas key looks good probably not a MIM gas key. If the carrier and key are chrome lined inside it probably a decent carrier.

The bolt should at least be stamped MPI, it is probably not a C158 bolt, but you'd have to contact YHM to find out.

The other possibility, if the carrier is good you could buy a BCM bolt alone since that is the most critical component (you should buy a spare cam pin too). Put the BCM bolt in the YHM carrier and keep the YHM bolt for an emergency spare.

Good luck and enjoy.

I had exactly the same idea before I saw your post. I think this BCG is OK, it's functioned for about 300 rounds with no issues, so it'll make a good range spare.

@ C4LT1: PM sent.

[jahrule]

To keep things interesting, here is a picture of the top of the BCG... the gas key staking looks pretty good to my untrained eye. What bothers me is the bolt itself is completely unmarked (and yes, I have taken it apart to check). That said, this BCG seems decent enough for how I use the rifle. I saw a 3-page thread here on YHM BCGs, but it didn't seem to reveal a lot of information- so I threw this picture out there for future reference, if nothing else.

It does look like it is properly staked. Like another member suggested, call yhm and ask them.