AR brass very sooty

[Coonman300]

A friend of my sons came to our farm today to get me to shoot his AR. Said he couldn’t get it sighted in. The gun was shooting all over the place at 50 yards…literally- 15-20 inch group. I assumed the scope was bad and he said it had taken some severe blows. I looked at his brass and it was solid black from soot. I am not knowledgeable at all about an AR and didn’t know if it was common for the brass to be this black. I was going to put a spare scope on it but before doing that I wanted to get some opinions on the brass. Base and rings are tight. This is a factory 6.5 Grendel AR and factory ammo.
Thanks!

 

[karrarararararar]

My guess would be the powder they are using. Probably a dirty ball powder. It's also possible it is on the weaker side being that it is factory ammo, causing a poor seal with the chamber.

 

[CJ6]

Does it have an adjustable gas block ? I've seen that when the adjustment was "wide open".

 

[Coyotefurharvester]

Even suppressed and ball powder my brass isn't that dirty. If I run starter load weights the neck, shoulder will have some soot. I have cheap non adjustable gblocks.

 

[Kevin1990]

I’ve got a 6.5G that I reload for with ball powder. My spent cases sometimes look real bad, but never anything like that. Curious of what the culprit is

 

[DGP4]

I have never seen factory ammo soot like that. I'd return the upper to the manufacturer if possible or have a gunsmith look at it.

 

[BobT]

I mostly run my ARs suppressed and the brass is not nearly that dirty.

 

[Coonman300]

The kid wasn’t too worried about it…he didn’t have time for me to swap scopes. He said the gun was about 7 years old and he’d probably shot less than 100 rounds Thru it. Said he’d never cleaned it either. I know nothing about an AR so I don’t know about the gas block. I suspect it will go in his closet for a few years and be forgotten about. I’ll suggest he get a gunsmith to look at it. Thanks guys!

 

[Toddmack]

I would check the headspace of his factory round against a fired round. As said above, that is dirty brass even for suppressor muffled brass.

 

[tommeboy]

He had oil in the chamber. Clean it up well and don't oil it.

 

[abishai]

Looks like someone is running H335

 

[avidflyer]

Dont know why, but I have 2 AR service rifles, high end builds and both look like that with factory mk262 or hand loads. They both eject at the so called perfect 3:30 spot.

 

[MGYSGT]

20" group at 50 yard. Barrel loose????????? Scope loose?????????