Scratched brass

[Snuby642]

This is a fairly deep scratch in the shoulder.
I have eliminated my reloader.

This comes from my 6.5g midway upper , (stoner) 20 inch.

I am running an h2 buffer and nothing else special.

75 rounds the same.
I could use some diagnostic help.

 

[hlee]

Sharp corners on locking lugs. The ejector pushes the brass into them during extraction and ejection.

 

[AIAW]

Sharp corners on locking lugs. The ejector pushes the brass into them during extraction and ejection.

Exactly. Beat a whole batch of Lapua brass up this way, sadly.

 

[Snuby642]

So i took a careful look.
Extractor edge, like a razor.
And then run a finger inside edge of bolt face.
Definite sharp spot on at least one lug.

Any suggestions on debur / smoothing this, kind of a tight spot.

Would have thought it would wear in by now.

 

[flyright]

Proof that brass doesn't wear steel very quickly. I'd use a small stone but I know a lot of guys use a Dremel with a polishing tip. With a stone, I feel that I can better control it and only take off the burr and no extra metal. A couple of careful strokes with low grit stone and your done. Flush it out from the muzzle really well. My .02.

 

[Snuby642]

I have a tri corner stone, will see if it fits in the am.
Thanks.
Actually if not may see if a dremel stone on a rod will get in there hate to dissasemble if avoidable.

 

[hlee]

The scratches are caused by the locking lugs in the barrel extension, not by the bolt or extractor. That is where your attention should be.

 

[rpoL98]

I usually debur those 2 corners, on the inside of the barrel extension locking lugs, with a hand-held 1/4" x 4" triangular stone abrasive file. Also smooth out the edge from the inside corner of the BE locking lug, to the outer corner, that the brass gets dragged along on. You can figure out which lugs it is if you visualize where your ejector is pushing the brass towards, and where the extractor is, when the bolt is coming back. About 2 o'clock to 3 o'clock position as you're facing the barrel extension.

 

[flyright]

+2 on the above - that's what I was referring to.

Edit: I did leave one of mine where it left a very slight 1/4" long scratch mark just below the shoulder of the case. I always knew what gun that fired brass came from. It polished off during case prep but helped me sort my cases.