Bolt Face Etching

[CPAjeff]

Quick question for you gun nuts, from a functionality standpoint, should one be concerned about the etching on this bolt face?



The backstory - a neighbor of mine, who is new to hunting, brought over his new rifle to show me. The rifle was purchased off of gunbroker.com and the condition was "new, old stock." Yes, it's a 6.5 Creedmoor . . . enter all the 6.5 manbun jokes here . . . Anyway, he and I went through the process of cleaning the new gun and removing all the factory grease/particles. I was wiping off the bolt and found etching on the bolt face. Obviously this gun has been fired, but hoping the etching is pure cosmetic (I'm a bit concerned that the rifle may have more problems stemming from the etching - either some extremely hot rounds went down the tube, or some bad primers were the culprit).

 

[marksjeep]

Is that completely cleaned up? Can you feel it with a pick?

 

[CPAjeff]

Is that completely cleaned up? Can you feel it with a pick?

Yes, that’s after I cleaned it. I didn’t try scratching it with a pick. Good idea though!

 

[Laelkhunter]

I think factories are still using "proof" rounds to test the firearm. They exceed normal pressure. Could it be from that?

 

[antelopedundee]

If it has been fired [other than proof testing] it's not a new gun. IMO it looks like someone at the factory failed to polish it. Polishing it might create an excessive headspace problem. Shoot it and see, but let the seller know about the issue before you do.

 

[WapitiBob]

Unless my eyes are failing, I can almost read the case head stamp.
Way way over pressure to do that. You should be able to clean it up with some 600 grit.

 

[CPAjeff]

I think factories are still using "proof" rounds to test the firearm. They exceed normal pressure. Could it be from that?

This is it! My neighbor contacted the factory - Christensen Arms - and was told the etching is caused by the proof rounds. Thanks for the help!

 

[WapitiBob]

CA is notorious for over pressure.

 

[antelopedundee]

This is it! My neighbor contacted the factory - Christensen Arms - and was told the etching is caused by the proof rounds. Thanks for the help!

Wouldn't that mean that the metal in the bolt is TOO soft?

 

[WapitiBob]

I believe the brass plasticised under pressure and adhered to the bolt face.

 

[buffybr]

I've seen that happen with blown primers from too hot of a load. Back off the load. The minor etching doesn't hurt anything.

 

[CPAjeff]

Wouldn't that mean that the metal in the bolt is TOO soft?

In my mind, yes. I've shot a few different brands of rifles and never seen this happen.

 

[cahunter805]

This is it! My neighbor contacted the factory - Christensen Arms - and was told the etching is caused by the proof rounds. Thanks for the help!

That sounds ridiculous to me. That bolt should not have left the factory in that condition but seems typical of CA.

 

[brockel]

This is it! My neighbor contacted the factory - Christensen Arms - and was told the etching is caused by the proof rounds. Thanks for the help!

Man I’ve owned a few Christensen rifles and have worked up loads for a few more than that and I have NEVER seen a new rifle come that way.

 

[Coyote Assassin]

I see another potential issue. At 10 o'clock the blueing is worn off, probably from the bolt coming in contact with the breech. Color the bare steel with a black sharpie marker and cycle the bolt several times. If the marker is gone your buddy has issues. I've seen a bunch of rifles over the years with accuracy complaints, and bolt contact with the barrel is at or near the top of the list. It's a major cause of those pesky flyers.

 

[antelopedundee]

I see another potential issue. At 10 o'clock the blueing is worn off, probably from the bolt coming in contact with the breech. Color the bare steel with a black sharpie marker and cycle the bolt several times. If the marker is gone your buddy has issues. I've seen a bunch of rifles over the years with accuracy complaints, and bolt contact with the barrel is at or near the top of the list. It's a major cause of those pesky flyers.

Would a proper replacement bolt fix the issue or is there more to it than just the bolt?

 

[Coyote Assassin]

If the bolt is indeed touching then you have two options....
1. Send the rifle back to the manufacturer and have them deal with it.
or....
2. Get it to a gunsmith. The correct way of resolving the problem is to pull the barrel and increase the depth of the counterbore to the proper clearance. $$$

 

[p_ham]

I see another potential issue. At 10 o'clock the blueing is worn off, probably from the bolt coming in contact with the breech. Color the bare steel with a black sharpie marker and cycle the bolt several times. If the marker is gone your buddy has issues. I've seen a bunch of rifles over the years with accuracy complaints, and bolt contact with the barrel is at or near the top of the list. It's a major cause of those pesky flyers.

That's just brass transfer from pushing the cartridges from the magazine.