Recently, I have seen two different AR pattern firearms that accumulated quite a bit of brass in the receiver area. Both of these rifles showed damage to the spent brass at the neck and what I believe is called the shoulder. It would appear that this was caused by the feed ramps. Is this common? One of the weird things is some of the brass shavings were just that little curls of brass about 3/16" wide.
Brass particles in the receiver
- Thread starter Daniel L
- Start date
Any chance you could post a few pics of the inside of the receiver where the brass is accumulating, a pic of the feed ramps & chamber?
Also can you provide any information as to the make and model of the weapon, caliber, ammunition used and if the problem is occurring with what types of ammunition if you have tried different types, and what magazines have you tried?
Small particles of brass are generally something that happens, which comes from the lip of the casings where the extractor slips around it during the locking cycle. The brass particles will accumulate in several places like the bolt face, ejector assembly, firing pin channel, bolt catch, lower receiver, trigger group, barrel extension, and upper receiver.
So a few pics of the brass shavings and receiver areas, fired brass, bolt face, etc, would help tell the story to see if this is normal or not, and if not then what is happening. So the more details you can provide, will help give us some clues.
CY6
Greg Sullivan "Sully"
SLR15 Rifles
TheDefensiveEdge.com
(763) 712-0123
Also can you provide any information as to the make and model of the weapon, caliber, ammunition used and if the problem is occurring with what types of ammunition if you have tried different types, and what magazines have you tried?
Small particles of brass are generally something that happens, which comes from the lip of the casings where the extractor slips around it during the locking cycle. The brass particles will accumulate in several places like the bolt face, ejector assembly, firing pin channel, bolt catch, lower receiver, trigger group, barrel extension, and upper receiver.
So a few pics of the brass shavings and receiver areas, fired brass, bolt face, etc, would help tell the story to see if this is normal or not, and if not then what is happening. So the more details you can provide, will help give us some clues.
CY6
Greg Sullivan "Sully"
SLR15 Rifles
TheDefensiveEdge.com
(763) 712-0123
Yondering
Regular Member
As Greg said, small brass particles/flakes are common from rough or stiff extractors damaging case rims.
Small shavings though sound like the back side of your barrel extension lugs may be really sharp. It's common to see scratches on the bullet of an extracted live round from those lugs, but no so common to see them actually damage the brass. Pics would help.
If it's just sharp barrel extension lugs, you can gently blend those sharp edges with some emery cloth. It doesn't take much, you're just trying to break the sharp edge, like trying to dull a knife blade. You don't need to do all of them either, just the couple closest to the ejection port, you can see which lugs the brass rubs against when you extract a round.
Of course if you're not confident in doing that yourself, it's always better to take it to someone who is.
Small shavings though sound like the back side of your barrel extension lugs may be really sharp. It's common to see scratches on the bullet of an extracted live round from those lugs, but no so common to see them actually damage the brass. Pics would help.
If it's just sharp barrel extension lugs, you can gently blend those sharp edges with some emery cloth. It doesn't take much, you're just trying to break the sharp edge, like trying to dull a knife blade. You don't need to do all of them either, just the couple closest to the ejection port, you can see which lugs the brass rubs against when you extract a round.
Of course if you're not confident in doing that yourself, it's always better to take it to someone who is.
I would love to provide picks, but ever since Photobucket broke the internet, I haven't had an image hosting service and since I Qualify as gen X I'm no computer whiz. The brass definitely shows signs of damage from the feed lips, but the rim at the base didn't show any signs of damage to the cartridge. Please keep in mind I was referring to two different rifles I had recently had contact with.
While I prefer not to hold any particular brand in disregard in my posting, One was a friends fairly well regarded DPMS pattern 308 16" carbine gas. he told me he had recently done something to a spacer in the ejector because it had been malfunctioning in the form of a stove pipe. It functioned fine for 20 rounds, other than last round bolt hold open didn't function on a 10rd P mag. I did wonder if the curls of brass were residue from a previous extractor issue.
The Second was a 300 BLK pistol that also showed damage to the case in the same fashion as the 308. I am by no means a very experienced shooter, but I haven't ever seen that much brass accumulate in the upper before.
Of note, and almost a whole different discussion, I took the blk pistol apart and the internal bore of the upper receiver struck me as odd. I bore mic'd the area where the barrel extension fits in the upper. Off the top of my head, it mic'd at 1.0005. the bore then stepped up through the rest of the upper to I believe 1.004. the truly odd part is when I look through the upper from the rear, the bore at the extension is offset eccentric, tangent to the bottom of the larger rear bore.
While I prefer not to hold any particular brand in disregard in my posting, One was a friends fairly well regarded DPMS pattern 308 16" carbine gas. he told me he had recently done something to a spacer in the ejector because it had been malfunctioning in the form of a stove pipe. It functioned fine for 20 rounds, other than last round bolt hold open didn't function on a 10rd P mag. I did wonder if the curls of brass were residue from a previous extractor issue.
The Second was a 300 BLK pistol that also showed damage to the case in the same fashion as the 308. I am by no means a very experienced shooter, but I haven't ever seen that much brass accumulate in the upper before.
Of note, and almost a whole different discussion, I took the blk pistol apart and the internal bore of the upper receiver struck me as odd. I bore mic'd the area where the barrel extension fits in the upper. Off the top of my head, it mic'd at 1.0005. the bore then stepped up through the rest of the upper to I believe 1.004. the truly odd part is when I look through the upper from the rear, the bore at the extension is offset eccentric, tangent to the bottom of the larger rear bore.