I have a very particular feed issue with a couple of Gen 2 or 3 (probably Gen2) Bulgy Circle 10 5.56 AK mags. On exactly the 4th from the last round in the mag, I get a FTF. Seems like it tries to feed the 4th round fine, but the 3rd round under it seems like it tries to feed with it and slams into the lip of the feed ramp causing the bolt to stop. However, if I clear the malfunction it'll successfully shoot and cycle the last 2 rounds.

To be clear, the rifle does not have the same issues with the translucent smoke Circle 10 mags or Polish Beryl 5.56 mags; just the black C10 mags... I even swapped the spring and follower from the smoke C10 mag that works over to the the black C10 mags and they'll still have the same feed issue.

Rifle is a suppressed Arsenal SLR 106CR that's running a large bore KNS Precision adjustable gas piston to compensate for gassing issues, and has been to InRange to have the out of spec selector stop plate milled to proper spec.

Thanks



What the 3rd round under the bolt looks like:

How does the bullet guide look?

AJ

I took my SLR-106 out for the first time this weekend and had the exact same problem with one of my Circle 10s. Weirddddd

So I decided to revisit this since the black C10 mags are some of the best 5.56 AK mags you can get, and I hate to just have a few laying around I can't use.

Turns out for some weird reason (maybe due to increased mag follower tilt when the magazine is almost empty?) the front of the bottom of the bolt carrier that rides over the hammer and magazine was catching the rim of the cartridge as it fed the next cartridge into the chamber.



With some light file work, I contoured the front of the bottom of the bolt carrier to help it slide over the cartridge rim, rather than catch it. I also removed a small amount of material from the top of the magazine catch to allow the magazine to flex downward a bit when the carrier puts pressure on the top of the next round.

When I was satisfied that it likely wouldn't happen during live fire by carefully hand feeding rounds with only 4 rounds in the mag to replicate the issue, I took it out back and test fired it.  I ran several batteries of 4 or 5 rounds in the black circle 10 mags that were having the issue and this seems to have remedied the issue. I may try and post video later this week.