300BlkTalk

Hi all,

New to the forum, apologies if I've messed up the formatting somehow! I’ve seen some other posts that are kind of like this one, but aren’t experiencing quite the same thing I’m seeing. Was wondering if anyone might know a solution!

This has started happening out of nowhere. Prior to last weekend, I had ZERO issues with my 8.5” Aero 300BLK upper, apart from it roughly chambering rounds. Apart from that, it was operating flawlessly. But, I took it out to the range, and it started failing to feed on every single shot, from any magazine. I’ve tried every magazine I own (all are 556 Magpul mags), and not a single one will work (when they worked just fine 2 weeks ago). It happens when I hit the bolt release, and when I manually rack it as well.

It seems to only be able to pick up the first round if the mag is half-ish full. I’ve attached some pictures of the issues.

It’s definitely the upper somehow. I’ve tried different BCGs, and buffer springs. Same issue. I’ve also tried cleaning and lubing the crap out of it…no luck.

I’m totally stumped on this, and any help at all is greatly appreciated. Thanks!

are you using the same ammo? or did you switch ammo too?

can you give us details on the specific ammo?

I also switched ammo. I started having the problem with Wolf steel ammo, which carried over to my brass ammo (can’t remember the manufacturer for the life of me. It was a blue box of 100, I remember that).

After meeting with my local gunsmith, we tried a surefeed metal mag, and it seems to have corrected the problem. It’s bizarre that it started happening out of nowhere, though.

Check your gas block im betting its loose!

Take a pic of the feed ramp, from this angle it seems pretty steep and not clocked right.