6920 Bolt Question

[doddste4]

I just picked up a NIB Colt 6920 over the weekend. I stripped it down today and the bolt has some weird discoloration on it that I have never seen on any bolt before. Just wondering what it might be. I tried to scratch it of with my fingernail, but nothing came off. Thanks in advance.
Steve

[markm]

Have you tried soaking it with clp and brushing it?

Never seen that before. Doesn't look like it'd hurt function, but I'd try to get it off.

[doddste4]

Already tried that, no luck. Also noticed that it is difficult to put the bolt back in the bolt carrier.

[spamsammich]

that's because you have to compress the rings, perfectly normal. That discoloration is probably a poor cleaning job prior to the finishing process. If it really concerns you, I'd show it to whoever you bought it from.

[doddste4]

Im not new to AR's, but I am no expert either. I have plenty others including another 6920 and haven't ever needed to compress the gas rings. Can you explain how to do this.

[markm]

Already tried that, no luck. Also noticed that it is difficult to put the bolt back in the bolt carrier.

Different than other ARs you've dealt with? If so, CONTACT COLT. Get it replaced.

Does the Bolt have the MPC markings on it?

[doddste4]

Yeah, its got all the correct markings. Ill just contact Colt when I get a chance. Thanks for the reply's.

[spamsammich]

Im not new to AR's, but I am no expert either. I have plenty others including another 6920 and haven't ever needed to compress the gas rings. Can you explain how to do this.

the rings compress when you push the bolt into the carrier.