Any advice on a 458 SOCOM upper?

[DrHenley]

I think what I am going to do is just drill two holes somewhere below the webbing slot, and bolt one of the M-LOK QD swivels on. Probably need to cut a steel plate to go on the opposite side so I don't pull through the thin plastic.

[Semper Paratus]

Doc
Of course if you are frugal (my 31 yo daughter calls it cheap) like me you can rig a ring using the available stock hardware and paracord. I rigged a QD at the rear of the receiver but with a full length A2 Rifle stock it rode too high beating my face and jaws up in a 2 point sling. Understand I am 6'4" 250# with a giraffe neck so an A2 stock for everything but two point slung is perfect. So I rigged a ring on the off side using paracord, the installed sling loop and a snap hook. Works fine. I have a photo but can't post it here. PM with an email or text number and I can send it.
Hal

[DrHenley]

Yes, I have been pondering similar such solutions. I just need some sort of ring on the side. The fixed swivel at the bottom won't let me carry the way I want to and need something higher up.

Here's a novel thought...Maybe I can just use the webbing slot as a webbing slot! LOL It's in the right position. Put some kind of strap through there that wraps around the upper part of the buttstock, and has a loop on the end that I can clip to.

[Semper Paratus]

Your local tractor supply has brass and nickle plated rings that work well with an HK clip, like you showed on the sling up above. That is how I have one of my "carbines" rigged with paracord on the A2 stock. Even easier with the web slot. Paracord is easy to tie off and secure....webbing MEH.