Chrome Pitting in LMT Bolt Carrier?

AR/M4 AR Technical Discussion
1

Hey guys,

I was cleaning off my carrier group yesterday after putting 120 rounds through the gun and i noticed that i had a small 2mmX1mm long rust spot in my semi auto bolt carrier group. The rust spot is located on the inside of the carrier group about an inch from the throat of the front of the carrier. It looks like the chrome lining wore off.

Is this common? Ive put about 700 rounds on this carrier total and it is ALWAYS lubed and cleaned properly. I have never used any aggressive solvents nor have i used anything stiffer than a paper towel to clean off the chrome lining.

There are no jagged burs or defects in my bolt assembly.

Will this cause any problems with the function of the gun?

At this point in time im just going to shoot it anyway because it still functions but im wondering if anything catastrophic can result from this.

2

Its very well possible it is not rust and the stuff that LMT uses in testing. If its on the surface and isnt dug in that is what it is.

3

It is dug in.

There is a noticeable edge around the spot.

Im not terribly proficient at macro photography but ill try and get some pictures asap.

4

Interesting hmmm.

5

I’d email LMT and let them know what you see.You can try calling them but the phones are very busy there as Ive found out lately.
More than likely they will want the part for inspection.If there is a defect they will take care of it.
I’d be willing to bet LMT would not be happy to see chrome coming off thier parts though.So I’d for let them know no matter what you decide to do.
Only thing that might happen from a rough spot in the bore of the carrier is short gas ring life.