My wife just bought a MP15-22 pistol and I am looking to outfit it. I would like to add a sling but not sure the hole in the shoulder stock would be the best place for a sling attachment. Is there another place attach a sling? I am looking for less than a carry method but a way to use a sling to help stabilize the pistol during firing while standing. I was thinking of creating an attachment point to the handguard

One end of the sling will have to go in the hole in the arm brace. The other will need a specialized attachment that fits to the slots in the handguard, commonly called M-LOK.

This firearm isn't designed to be fired from the shoulder, and doesn't have a shoulder stock. It has an arm brace. Your forearm goes up in the slot between the two plastic pieces at the rear, and the velcro strap on the brace goes around your the plastic and your forearm to secure it . . .

(Yes, you can put it up against your shoulder, but ATFE guidance on that has changed over the last few years.)

__________________
Wisdom comes thru fear . . .

My arm brace extends and could possibly be used against my shoulder unless ATFE will cite me for doing so.

I got a M-lok and put it on the handguard that catches the front of a sling nicely. I am not able to get a sling clip through the
hole in the shoulder brace. Is there some kind of loop or attachment I can put through that hole?

They're out there. Google is your friend. The most common for this application have large clip on one end and a push button sling swivel on the other . . .

__________________
Wisdom comes thru fear . . .