Copper shavings when cleaning 6.5 barrel

[Gatorshark]

I thought this would have cleared up by now in my Criterion 18" creedmoor barrel, but no.

I shoot my own reloads with carefully prepped brass in my Mega Maten. After 100 rounds, i continue to get these small copper shards out of my barrel while cleaning. Accuracy isnt what it should be, but i clean and clean between firings and still get this on my patches.?

 

[Codiekfx400]

Are they coming off your cleaning rod?

 

[Precision Underground]

Are you sure it's copper and not brass from the receiver/chamber?

 

[Gatorshark]

Too much of it. Brass casings look good. This is from SST jacket it looks like.

 

[Precision Underground]

Too much of it. Brass casings look good. This is from SST jacket it looks like.

You probably wouldnt see evidence on the brass. AR10s are hell on brass and will shave/flake bits off around the case head/rim. IMO if it was copper it would not be coming off in chunks like that. It is either going to be blown out the barrel or fused to the barrel.

 

[Precision Underground]

I guess if the lugs are stripping bits of copper off upon cambering you could get some of that.

 

[ChitownCopper]

To much twist possibly spinning the bullet apart or u have a burr in your barrel

 

[Sieg]

Maybe invest in a Teslong bore scope so you can inspect the finish of your chamber, throat, and gas port.
Troubleshooting issues like this are where they are good tool to have IMO.

FWIW - This is the barrel port in my Ruger SR762 with 160 rounds through it.

 

[Gatorshark]

You probably wouldnt see evidence on the brass. AR10s are hell on brass and will shave/flake bits off around the case head/rim. IMO if it was copper it would not be coming off in chunks like that. It is either going to be blown out the barrel or fused to the barrel.

You know that is prolly it. It has to be brass from casings. Ill just need to try and clean/polish the ramps and extension a bit.

This has to be causing some fowling too, no?

 

[Precision Underground]

You know that is prolly it. It has to be brass from casings. Ill just need to try and clean/polish the ramps and extension a bit.

This has to be causing some fowling too, no?

Ehhh I doubt it’s getting stuck in the barrel. You are likely picking that stuff up as you pass the lug area with the patch. It never hurts to knock down sharp edges though as long as you don’t go too far. Metal mags can have sharp edges too that will dig into the brass.
Accuracy-wise if you are having issues it can be a rabbit hole with an AR, especially a large frame. Do you have other gas guns that you shoot well? It takes twice the fundamentals to shoot .5 with a large frame than it does with a bolt gun.

 

[Reverie Ranges]

It sounds like the rifling is burred IMO. If you can get a round off into some ballistic gel, check for any defects in the expended round. Borescope for good measure. Possibly replace barrel and repeat.

 

[DRandi]

Odds are it’s small flecks of brass that are getting knocked off as the bolt rotates in and out of battery. Remember the case is still under pressure and stationary when the extraction cycle starts. Common sources are the extractor and ejector hole(s).

 

[Gatorshark]

Yes that makes sense. Cleaning from the chamber to the bore I'm just pushing though.

Have a much better idea now what to look for. It's a Criterion match barrel and a Rubber City bolt. May just need a little polishing.

 

[Merle]

What kind of accuracy are you getting with the Criterion barrel?

 

[Gatorshark]

If I do it right with an un fouled barrel, it does 1/2 inch groups with 129gr SST and 4250.

 

[theLBC]

not using a bore guide?

 

[Gatorshark]

I'm chamfered all cases and carefully prepped. I even pulled some bullets to see if there were shavings. They looked good.

I'm pretty sure based on replies here it's from the feedramps and/or bolt. This is only me 2nd large frame semi. Never encountered this on several AR15 sized rifles.

 

[Greg Langelius *]

While looking for the cause of shavings, I would check the magazines too.

Sometimes there's interference during the feeding process. If they're metal, there may be streaks of copper, etc. on the cartridge path disclosing that interference.

I'm concentrating on buying Magpul PMAGs as I acquire new magazines. My guess is that they won't strip metal off the cartridge.

My PA-10 is new, and is my first large frame AR. I've stuck with PMAG LR/SR Gen 3 magazines (10rd) and Hexmags (20rd) since the beginning.

Greg