Brass and Ejection Q?

[dstroyed]

Need help. What is causing these marks on my brass? Is it something to be concerned about?

I had a stock 16” DPMS. I just put in a trigger and JP adjustable gas block. I test fired today and adjusted the gas block per instructions. Ran 50 rounds through it without any issues other than the brass markings.

Pictures are the best.

Thanks

[ajg308]

Could be where the bolt is hitting the case to strip it out of the mag. You might have too much gas going into the system. How far is the brass ejecting? If is is going further than before you changed the block, turn it down a bit. Almost every AR I have been around throws brass 6-10 feet from the shooter.

Need help. What is causing these marks on my brass? Is it something to be concerned about?

I had a stock 16” DPMS. I just put in a trigger and JP adjustable gas block. I test fired today and adjusted the gas block per instructions. Ran 50 rounds through it without any issues other than the brass markings.

Pictures are the best.

Thanks

[Sean Gaines]

look for a high place on your breechface. I had a similiar problem with my pistol making similiar marks

[dstroyed]

ajg308, i had not thought about it being a mag issue. I need to look at that. I think i may have used a new to me used mag yesterday.

Breechface and everything i can see and familiar with looks good and clean through the ejection process. I really feel the gas is adjusted correct. It is throwing brass about 8-10' in a pretty neat pile.

[mlmiller1]

Mag issue? I can't see how that could be it but I don't know nuttin' anyway. hahaha.

Hope you figure it out. If you don't reload, it might not matter to you but it looks to me like something is getting too much pressure. Be sure to post what it was when you get it figured out, ok?

MLM