MSR 10 Hard on brass

I recently purchased a MSR 10 in 6 cm, love the gun and it will shoot.

My concern is it seems like its awful hard on brass, I am getting 2 "scrapes" about 1/8" apart from the begining of the neck to the end, this was on virgin brass, 6.5cm necked down and 1st firing, all the cases seem to have this issue. I had some previously fired 6cm brass that was fired in my 110 DT, I believe this was their 4th reload thru, I anneal each time, FL resize, trim, etc., and once I fired them in the MSR 10 minute splits in the case neck.

Any ideas?

Thanks

MSRs are generally hard on brass all the way around in my experience.
I dinged up some virgin Lapua .308 the first time I shot it.
Pretty sure mine are dinged near the neck from when the brass gets launched hard into the shell deflector and bounces off.
I have to chalk it up as an expensive lesson.
Now I try to load range pickup brass for my ARs and keep it in a separate can.

Many, many AR’s are, let alone some other auto loaders. Especially when new, because there are lots of sharp edges on inside moving components. I’ve built several AR’s that dented, left scratches & even gouged the brass. But I had a Cetme (HK G3), that just absolutely mangled the brass. The Delayed-Roller Blowback extraction was so violently forceful, it would literally rip the cases in half! The cases it didn’t, looked like a shirt that Freddy Kruger had his way with. It was fascinating. Luckily, 308 was like $0.10/round back then.

I’d shoot it awhile. Give it a few hundred rounds see if it starts smoothing some edges a bit.

Feel the mag feed lips, use something to polish the edges smooth. I keep a lot of cratex bits around for this. If that doesnt stop it then....Work on the feed ramps. Watch some youtube vids on reworking AR feed ramps. I use sanding cones. Take it slow and work on the sharp edges in the barrel nut. The aluminum part of the ramp will eat away fast if your not careful. Stay away from the chamber. you will probably have to separate the upper and lower and go in through the loading port. Hold it in a vice and us a lot of light. MAgic marker or layout die shows you where you are removing metal.


Brass takes a long time to remove or wear down steel.

Sharp corners on the barrel extension locking lugs. When the case clears the chamber, spring pressure from the ejector forces it to hit the lugs on the right side. Whenever I install an ar barrel I use a rubber polishing wheel and soften the edges of the locking lugs before assembly.

Quote:

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Originally Posted by vulcan

Sharp corners on the barrel extension locking lugs. When the case clears the chamber, spring pressure from the ejector forces it to hit the lugs on the right side. Whenever I install an ar barrel I use a rubber polishing wheel and soften the edges of the locking lugs before assembly.

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This too.