[Jarhead0311]

Finally got the MCX SBR, 300 B.O. short barrel & can all squared away, shot it twice & love it but I noticed a lot of tiny copper flakes all over the lower & back half of BCG, anyone else have this ? Never saw this on 516 or or M-16.

 

[cdavis]

Sorry to not have any good input on your issue but welcome from Arizona and congrats on the MCX.

 

[kansascity45]

Welcome to Sig Talk, and Congrats on your MCX SBR kit!!

You've accomplished what many, including myself seems impossible. I mean, cobbling together the rifle - along with the necessary components from SIG, and the double dose of ATF paperwork - All while you're still walking this earth is an incretable achievement!!

Your copper flakes are a new issue for me. I'll suggest that these may be coming from a slight alignment problem with the barrel extension's M4 feed ramps. It's a guess that some copper could be shaved off the bullets as they're fed into the breech, and running suppressed has enough blowback pressure to push these flakes into the rear of the upper receiver.

Make sure the barrel's 2 positioning pins are fully inserted into their slots on each side. If the barrel's good, then call SIG customer service. They'll want to take a look see for ya...

Cheers

 

[Jarhead0311]

"copper flakes"

Thanks, good idea ! I'll take a closer look before I clean it next time, but yeah I'll call sig as well. It functions flawlessly otherwise from day one !

 

[kilyung]

Congrats! I'm almost there with ya. Just need my suppressor compatible handguard.

 

[kansascity45]

Yeah, it's like playing poker. My 9" 300 barrel isn't much use until I get either the short handguard SIG doesn't now have, or the ATF coughs up a suppressor stamp I filed on April 2016.

Until something brakes, we'll keep adding ammo when it's on sale

Cheers

 

[boris95]

kansascity, did you have a slamfire with the Freedom Munitions, before the BCG upgrade?
That is what I was using when I had my slamfire. Do you know what primer FM uses in reman 300blk?

 

[kansascity45]

kansascity, did you have a slamfire with the Freedom Munitions, before the BCG upgrade?
That is what I was using when I had my slamfire. Do you know what primer FM uses in reman 300blk?

No, I'm still looking for a trump card, and haven't yet fired a single round in 300. We're hoping SIG's new firing pin locking lever resolves those slam-fire issues - so we can run this cheaper ammo. As you know, there's a significant price brake on these...

Cheers