Gunsmithing bolt face "plating" from brass

[Osmosis]

Here's my dumb question for day:
I did a search and couldn't come up with anything pertinent. everything I could find had to do with shavings and chips.

My extractor isn't shaving from the case like I read can happen, but my bolt face is being "plated" by the brass. My other rifles haven't done this and have way higher rount counts. I am at only 110 rounds total with this new rifle.

Normal for a 700 sps? I'm just gonna clean up with with some solvent but should I take it to my gunsmith to polish?

It's at the point now that my primers are rough after firing, and if I close the bolt on a round and don't fire you can see where the primer cup is being scratched.

 

[Beef82]

Re: bolt face "plating" from brass

I think every center fire rifle and pistol I have experiences some brass transfer, it just about wipes off, I've never noticed it scratching the primers. I wouldn't worry about it, you might want to make sure your bolt face doesn't have any damage/protrusions that might be the underlying cause.

 

[Osmosis]

Re: bolt face "plating" from brass

Thanks for the reply.
I've never had this happen to this extent, for that matter my savage 10 doesnt get any at all. My handguns get some suit/carbon on the face but never any brass that I can remember.

I went to town on it with brass and fine wire steel brushes with solvent and that stuff was really on there. I had to use dental picks and put the elbow grease into it. got 95% off and no more primer scratching afterwards.
I couldn't see any defects or burrs or anything in the face itself causing the buildup, and it presents in a couple "Rings" of this fouling.
First a ring 2mm's wide around the firing pin hole. then none for a mm or two, then a narrow ring, then none and then a several mm ring around the outside which is the widest and thickest.
The fouling was thickest on the opposide side as the plunger.

A friend mentioned it being possible that my chamber had a burr and that the brass instead of turning with the bolt is sticking in the chamber and that friction against the bolt face is depositing this. The brass looks great with no scratches or anything so I don't think that's the issue.

 

[Greg Langelius *]

Re: bolt face "plating" from brass

Brass deposition on the bolt face is a normal and customary result of firing and bolt rotation. It should wipe right off with a cloth and copper solvent. It is no cause for concern, and removing it should be considered a normal part of the cleaning process.

 

[Blackbrush]

Re: bolt face "plating" from brass

My 700P MLR does it unusually so. My bolt is a bit stiff to open after firing with pretty moderate loads too. I've come to the conclusion that the bolt face is convex as most of the deposit is near the center of the face. We're going to true it up and hopefully see more normal behavior.