https://photos.app.goo.gl/Kvhq8eAr8wX3Ec236

Discreet Ballistics Selous rounds
Aero upper
Q 7" barrel
Toolcraft BCG

Happens with Shredded E2 mags. Have tried Lancer and magpul 300blk mags, but they ride a little lower and get the rounds caught on a gap between the feed ramps.

Rounds lock back on empty every time. But I can't get these to feed for the life of me.

Only happens with these rounds. Doesn't happen when I manually cycle the round

Any ideas?

I am about to give up on these rounds or try a brand new upper/barrel

Here's your pic:

I have no experience with your set-up, but that has to be putting out a lot of gas pressure. I would be thinking over-gassed and overspeed, and would consider a AGB and the heaviest buffer available, especially if running suppressed.

I have a question. How would being over gassed create that malfunction?

I have a 20 rifle with an FRT that has the same malfunction. The gas block front sight base is an adjustable JT that I have wide open.

It feeds great with USGI magazines but no joy with my ATI Schmeisser 60 rounder.

My best guess is actually the exact opposite of this. I had to swap the suppressor from a sandman to the 9k because I wasn't getting nearly enough gas (rifle felt noticably sluggish and bolt wouldn't lock back on last round)

Rifle still feels a little sluggish but the bolt is locking back consistently now. But then this failure showed up.