I have a magpul stock with the qd inset, and an MS4 sling. In the forend
I have qd mounts and the ms4 doesn't rotate. But every time I want to
use the sling, I have to untangle it, because the same sling into the magpul
stock keeps spinning.

Is there another qd sling mount I can get that doesn't do this, did I get the wrong one
or is there anything I can do? I love the combo otherwise.

Is this the sort of thing you're after?

Yes! Actually didn't think this was a thing. I was really surprised.

Anyway, email sent.