Pistol ARs with "brace": experience?

[Five_Point_Five_Six]

I have been looking into AR pistols and even looked at the Ruger at $559 and am wondering if there is a pistol with a shorter barrel that will work reliably?

Don't go below 10.5" and preferably 11.5" on 5.56 unless you hate ballistics and are just creating a meme gun.

Avoid Ruger. Proprietary parts.

If you feel the need to go under 10.5" 300 BLK is your best bet.