Gunsmithing Need Some Help - brass shavings on cleaning patch

[jab00]

I'm hoping that someone can help me figure out what's going on here.

The Issue:

While cleaning my 6.5 Creedmoor barrel today, I noticed what looks to be brass shavings on the first few patches that I ran through the barrel. Can anyone help me figure out what could be causing this?

The rifle is a switch lug build that's using a West Texas Ordnance lug. So, the barrel is just screwed in hand tight and then torqued to spec. As far as I know, a standard reamer was used to cut the chamber.

• This was the first cleaning that I've given the barrel after the initial cleaning that I gave it when it was picked up from my builder. I've taken it to the range twice before today and only ran an oil soaked patch down the barrel after each session (do not recall noticing any similar shavings on those patches)
• Since then, I've put 300 rounds of factory Hornady ammunition through the barrel
• I first noticed the shaving when I pushed a KG 1 soaked patch down the bore (see picture)
• I did notice that some of the necks on the brass have spots that look like they were chewed up a little (see picture for an example)

 

[RmeJu]

Is it possible is that your brass is too long for your chamber? This *seems* unlikely for factory ammo, but your brass mouths are chewed up and you've got shavings on your patches... any weird dimensions to your chamber? Did you measure the fired brass?

Or, since there damage doesn't look uniform, and the gun is new, maybe you have a burr somewhere that's nicking the brass, leaving it in the chamber, and you're pushing it out the barrel when you run the patch through?

I'm no expert, just a thought. I hope you get it figured out.

 

[jab00]

Is it possible is that your brass is too long for your chamber? This *seems* unlikely for factory ammo, but your brass mouths are chewed up and you've got shavings on your patches... any weird dimensions to your chamber? Did you measure the fired brass?

Or, since there damage doesn't look uniform, and the gun is new, maybe you have a burr somewhere that's nicking the brass, leaving it in the chamber, and you're pushing it out the barrel when you run the patch through?

I'm no expert, just a thought. I hope you get it figured out.

I haven’t measured the fired brass yet but I’m going to do that tomorrow. I’m also going to pull the barrel off and take a look at the chamber

 

[Boxcar]

I’d find how for sure what reamer was used for the chamber, wether it be a tight necked reamer or a worn out one.
Any resistance on primary extraction?

 

[jab00]

I’d find how for sure what reamer was used for the chamber, wether it be a tight necked reamer or a worn out one.
Any resistance on primary extraction?

I didn’t feel any resistance when running the bolt, either to chamber a round or to extract. The bolt actually runs super smooth when cycling.

I’m pretty certain that a standard SAAMI chamber reamer was used (not a match chamber or anything funky) but I’m going to verify

 

[supercorndogs]

Are you sure the damage to the mouth didn't happen when it was ejected?

 

[jab00]

Are you sure the damage to the mouth didn't happen when it was ejected?

That’s entirely possible - I was more or less putting The two observations together as symptoms of the same issue. What’s a little strange, and may just be a total coincidence, is that I didn’t see any of the same shiny rough spots on the necks of the 20 pieces of factory SIG match ammo that I shot yesterday with the 60 rounds of Hornady factory ammo.

 

[supercorndogs]

I often see a couple pieces that landed on their mouth on the concrete that look like that. I see a little brass on my first patch from time to time also. I could be wrong, but I don't worry about it. There a lot of opportunities in a couple hundred rounds to shave off a few little pieces of brass.

 

[jab00]

I often see a couple pieces that landed on their mouth on the concrete that look like that. I see a little brass on my first patch from time to time also. I could be wrong, but I don't worry about it. There a lot of opportunities in a couple hundred rounds to shave off a few little pieces of brass.

Good points - I’m mostly concerned about the potential of those shavings potentially scoring the rifling as they make their way down the barrel but I may just be overthinking this too much

 

[supercorndogs]

Brass is softer than steel. Its not going to score steel.

 

[jab00]

Brass is softer than steel. Its not going to score steel.

True - I’ll just keep an eye on this and not obsess over it. I’m going to start working on finding a hand load for this barrel and I’ll see what happens as I work through that and see if the trend continues with a trim length that I know is constant (or as constant as I can be)

 

[Wannashootit]

Are you using a bore guide for the cleaning rod?
If not, you could be picking up tiny brass shavings caused by the extractor/ejection with the patch before it gets into the bore.

Just a thought...

 

[jab00]

Are you using a bore guide for the cleaning rod?
If not, you could be picking up tiny brass shavings caused by the extractor/ejection with the patch before it gets into the bore.

Just a thought...

That’s an interesting point. I do normally use a bore guide when I clean but I misplaced the correct size tip for 6.5 somewhere so I cleaned without it and was just as careful as I could be to keep everything straight

 

[FisherT&C]

Did you use a brass bore brush? These maybe just be pieces that came off the brush during cleaning.

 

[jab00]

Did you use a brass bore brush? These maybe just be pieces that came off the brush during cleaning.

No - I only have nylon brushes

 

[jab00]

So, I just pulled the barrel and think I see where the shavings might be originating from in the chamber area.

From what I saw, there is a very small dull, brass shaded, mark on the steel where the rounds are feeding into the chamber. I didn’t feel any perceptible burr there and I also ran a cotton swab over the spot to see if it would snag, which it did not.

I’m guessing that it’s possible that there’s a very minute rough spot or burr there that is shaving a little brass as the round is chambering?

 

[Wannashootit]

There should be a slight radius to the chamber mouth for exactly that reason.
That it doesn't have a burr is irrelevant, it shouldn't be a sharp right angle.

if whomever chambered the barrel didn't do that I'd send it back to have it done; if you have a lathe simple enough to put it in the steady and lightly knock down that edge.

 

[Superjet]

A little emery cloth may fix you up.