RRA AR15 9mm Dirty Brass

[LJH]

I got to take my new 9mm RRA Ar15 out and put it through its paces today. It ran really well and was much more accurate that I expected. Only thing is that the brass it spits out is dirty. Not just a little blackened, but covered in soot. Is this normal?

 

[NavajoNPaleFace]

Powder residue.

Some powders burn cleaner than other brands.

 

[taliv]

are you shooting reloads?

 

[LJH]

WWB, and they came out of my pistol as shinny as new.

 

[taliv]

dirty brass in the reloading forum is usually indicative of not properly resizing. if you're shooting new ammo, my guess would be your chamber isn't properly sized. i dunno, but i doubt it's any sort of safety issue.

try this: get some calipers. measure twenty unfired rounds. measure ten after firing from your pistol. measure the other ten after firing from your carbine. compare.

 

[texfed]

We use Colt 9mm subs as issue, have for years...issue ammo is Winchester silver tip......we got drums of dirty brass....it's the nature of this weapon.

 

[ogree]

max chamber dimension for dependability result in the brass coming out of the weapon in that condition.

 

[taliv]

well, if it's a larger chamber on purpose, i guess it's ok

 

[JDGray]

Mine spits em out dirty, also I use, and have had great luck with nickel plated 9mm brass, clean up in the tumbler is three times faster then brass.

 

[Walkalong]

Mine dirties the brass up pretty good. Depending on the load it can be half the case to fully sooted up.

It is a blowback design and the case is pretty much moving as soon as it is fired. It can not seal well as it is simultaneously being pulled back and ejected while firing. A heavier buffer would help a little, but it is basically the nature of the beast, as texfed alluded to in an earlier post. The 9MM buffer is already much heavier than a standard buffer, but even heavier ones are available.

Spikes buffers

Slash's buffers

 

[LJH]

Thanks everyone! My mind is at ease.