300 BLK cases getting gouged?

[SkaerE]

have a CMMG 300 BLK upper that seems to gouge my brass right at the shoulder. not just a slight flattening, but a gouge to the point I can see shiny brass.

Any ideas to the cause?

 

[Austan]

Re: 300 BLK cases getting gouged?

Feed ramp need polishing? Does it happen if you single load?

 

[PowerstrokeOBX]

Re: 300 BLK cases getting gouged?

Check your magazines too.

 

[Eagle1899]

Re: 300 BLK cases getting gouged?

Locking lugs on the barrel extension.

 

[Eagle1899]

Re: 300 BLK cases getting gouged?

Sharp corners scratching the brass on feed/eject. May be able to ID the offender and knock the sharp one off with a stone or file...