Bushmaster ar-15 feed ramp issues

[slayfire]

I have a Bushmaster ar as the title suggest. I spend hours making very high grade ammo and unless I single feed the rounds the feed ramp(i guess) scratches the heck out of the bullet and brass. I do get better groups when I single feed due to this issue. Is there anything I can do to rectify this problem?
I loaned the gun to my brother for deer hunting with a 62gr TSX and when I got it back the round that he had chambered 5-6 times looked like it had been drug across concrete for a mile or so.

 

[taliv]

are you sure it's the feeding and not the ejecting?

the ejector spring puts a lot of pressure on the brass to drag the bullet across the lugs. if you use your finger to push on the brass while you're slowly pulling the bolt back, to keep the cartridge straight so the bullet doesn't touch anything while ejecting.... i bet it comes out without scratch marks.

 

[slayfire]

Thanks, I'll try that. It might be my imagination on getting better groups with single feed. I do most of my precision target shooting single feed anyway

 

[rcmodel]

Likely a bur or sharp edge on one of the barrel extenson locking lugs.
If you can find it with you finger?
Slot a wood dowel and wrap a peice of 320 grit black emery paper on it, reach in there, and smooth it out.

Some of the case body scratching further back can be caused by rough magazine feed lips too.
Thake the spring and follower out and use the paper on them a little.

rc

 

[taliv]

by the way, repeatedly rechambering the same cartridge is not something i'd recommend doing in your house with an AR15.

please make sure you keep the gun pointed in a safe direction

 

[slayfire]

taliv, I just checked and the problem is not with ejection. I will see if I can feel the bur tomorrow and try to polish it out if I can. Am I alone in have an ar that scratches bullets every time it chambers them?

 

[slayfire]

rcmodel, it is not the magazine unfortunately, every mag i have does it including polymer mags.