300 BLK Crushing Brass on a New Build

typz2slo · Post by **typz2slo** » Sat Feb 01, 2014 11:40 am

My son and I have assembled our first AR in a 300 BLK. The problem is that it is crushing the mouth of the case at about 5 oclock when looking into the chamber. Different mags, different manufactured brass produce the same results. Hand feeding a round and then drop the bolt it does not crush the case mouth.The brass are trimmed to 1.364". If I hand chamber a round. The pic is of the feedramps and receiver. Is the lineup off enough to cause the issue? Any help would be greatly appreciated.

smustian · Post by **smustian** » Sat Feb 01, 2014 1:35 pm

Only wear that I see is at the 7 o'clock position of the feed ramp. Nothing is obvious to give denting at 5 o'clock.

talonxracer · Post by **talonxracer** » Sat Feb 01, 2014 2:07 pm

Any pictures of the deformed brass?

typz2slo · Post by **typz2slo** » Sat Feb 01, 2014 3:15 pm

shouldnt be any wear at all. It has never been fired

typz2slo · Post by **typz2slo** » Sat Feb 01, 2014 3:23 pm

InMyHumbleOpinion · Post by **InMyHumbleOpinion** » Sat Feb 01, 2014 3:45 pm

Might try a little crimp.

typz2slo · Post by **typz2slo** » Sat Feb 01, 2014 4:26 pm

The bullet is a Lee 230gr TL. Ended up running the COL to 2.250" and a slight crimp. I can just see a mark but not bending the brass so maybe I will load a few with powder an see how they run. Also would it hurt anything to soften the sharp edge of the chamber mouth? This barrel looks like it has a sharp edge compared to others i have looked at.

smustian · Post by **smustian** » Sat Feb 01, 2014 7:10 pm

typz2slo wrote:The bullet is a Lee 230gr TL. Ended up running the COL to 2.250" and a slight crimp. I can just see a mark but not bending the brass so maybe I will load a few with powder an see how they run. Also would it hurt anything to soften the sharp edge of the chamber mouth? This barrel looks like it has a sharp edge compared to others i have looked at.

I would not do anything to the chamber yet. If it ends up being a barrel/chamber problem then you would have voided the warranty.

Suputin221 · Post by **Suputin221** » Thu Feb 06, 2014 1:24 pm

The problem is that your bullets appear to be seated too deep in the case. The pic is not clear but it looks like there is a section of unsupported brass right at the case mouth. This is why the case is being crushed. If the bullet is seated longer it will support the case mouth and prevent it being crushed.

Khackee · Post by **Khackee** » Mon Feb 17, 2014 6:12 am

What brand barrel is it?

300BlkTalk

300 BLK Crushing Brass on a New Build

300 BLK Crushing Brass on a New Build

Re: 300 BLK Crushing Brass on a New Build

Re: 300 BLK Crushing Brass on a New Build

Re: 300 BLK Crushing Brass on a New Build

Re: 300 BLK Crushing Brass on a New Build

Re: 300 BLK Crushing Brass on a New Build

Re: 300 BLK Crushing Brass on a New Build

Re: 300 BLK Crushing Brass on a New Build

Re: 300 BLK Crushing Brass on a New Build

Re: 300 BLK Crushing Brass on a New Build

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