Popping primers.

[Thomas Geistman]

I’m shooting factory loaded 5.56 ammo out of a AR-15, FN 5.56 chambered barrel and I’m popping primers out of the shell and they’re also showing signs of pressure on the popped primers. I don’t want to say the ammo manufacturer yet. The ammo is accurate for what this barrel is capable of.
Also, I’m getting a failure of the bolt to fully close about every 8-10 rounds. I drop the mag and action the rifle a few times and it feels a little sticky when it finally catches the round and strips it out. I’ve only shot probably 2-300 rounds through it. Always suppressed. Could the chamber already have carbon ring? Or is this barrel possibly really tight chamber? I haven’t checked with a go/no-go gauge but would that be my next step? Only thing that does help is tons of lube. Or could this be an ammo issue?

 

[db2000]

Easiest is to try another brand of ammo if that’s all you’ve tried in it
Also, after doing that first, then clean the hell out of it including feed ramps and chamber. Then retry both ammos

 

[bfoosh006]

As mentioned, clean the chamber and bore thoroughly.
Packing oils / rust inhibitors left in the FN barrel are quite possible.

 

[Thomas Geistman]

Well I cleaned the hell out of it and lubed the shit out of it like dripping wet bolt carrier and shot some different ammo. Had no malfunctions. Primers to me still look like signs of some pressure, but maybe this is normal? Didn’t loose a primer with this other ammo though.

I’ll try the original primer popping ammo here next.