Update: Independence 5.56 XM193I

[turnburglar]

I had a few blown primers out of the few boxes of independence that I had. Won't be purchasing again.

My Mbus requires the same amount of windage on my never been dropped on hardwood, f marked fixed front sight post. Contacted magpul and they said it's fine and run it as is.

[JS-Maine]

Neither am I and thanks for the info. The bright ejector marks are certainly present, and though I am not experienced in reloading it seems that these primers do appear somewhat flattened in comparison to other once fired factory brass.

I'm not liking the way those cases look, here's sometime I swiped from somewhere, maybe you can link to the article:

[GUNS Magazine, May 2010, “Reloading Puzzles & pieces thereof”, Glen Zediker]

Ejector Marks – In either case, ejector marks are a definite sign of pressure and the load should be reduced accordingly.

Flattened Primer – Where this condition is accompanied by other signs, it is due to excessive chamber pressure.

[Iraqgunz]

I burned through about 2K of that ammo since last summer and didn't have any issues.

[TomMcC]

The cases look to me like your rifle is over-gassed. I have a Bushwhacker that produced brass with that same type of ejector smear until I put a heavier buffer in it.

[Iraqgunz]

Who makes your barrel?

[JS-Maine]

Who makes your barrel?

BCM BHF Midlength Govt profile. BCM BCG. H buffer and blue Tactical Spring CS Spring.

[markm]

The cases look to me like your rifle is over-gassed. I have a Bushwhacker that produced brass with that same type of ejector smear until I put a heavier buffer in it.

Interesting. I chrono'd that stuff out of a 20 inch Colt and was getting WELL over 3300 fps. After 5 rounds and 5 pretty swipey case heads, I pulled the other 15 rounds down and used the components for making sane ammo.

I don't think this crap will blow a gun to bits as long as they have consistent powder charges, but it's right up against the red line and not worth the wear on the gun. Slinging a 55 gr FMJ that hard is like slamming your head against the wall.

[JS-Maine]

Interesting. I chrono'd that stuff out of a 20 inch Colt and was getting WELL over 3300 fps. After 5 rounds and 5 pretty swipey case heads...

I'm backing down on firing the rest of this. I have maybe 100 rounds left. Not worth it.

Purchased last Nov through PSA. Curious if others have fired the same lot and checked out their brass...which doesn't look so hot even before firing.

[TomMcC]

Interesting. I chrono'd that stuff out of a 20 inch Colt and was getting WELL over 3300 fps. After 5 rounds and 5 pretty swipey case heads, I pulled the other 15 rounds down and used the components for making sane ammo.

I don't think this crap will blow a gun to bits as long as they have consistent powder charges, but it's right up against the red line and not worth the wear on the gun. Slinging a 55 gr FMJ that hard is like slamming your head against the wall.

Since his barrel is a BCM and is not likely to be over gassed I'll try and score a box and chrono it out of my BCM 16" midlength. I will also try it out of my 20". I rarely shoot factory ammo anymore, but this sounds like a good excuse to try this stuff. It's looking like there are multiple reasons for ejector smearing.

[markm]

Yep. That's what I did. I saw it being discussed here and grabbed a box from Cabelas to try out.