the magpul plate sling adapter is great if you have the magpul sling, and use it like as a carry sling like costa does in the magpul videos. it would be pretty annoying to use with other types of slings like if you wanted to 'sling up' with a shooting sling.
there are cheap nylon slings like the old spectre gear ones that just wrap around the front of the forearm and velcro to themselves. there are also more traditional hunting sling swivel type mounts. and most stocks have a slot somewhere on them you can just stick the sling through.
but these days, i like flush cup mounts. you can get flush cup mounts that go on picatinny rails, or that fit into the slots on round handguards like vtac. and many stocks come with flush cups in both the front and back of the stock (butt and next to the receiver)
slings though are like a necessary evil. they're mostly a pain in the butt. none of them are perfect and they take a lot of practice/training to sort out where theyr'e not really in your way.
straps of heavy nylon are just a few dollars. the elastic and various plastic and metal buckle hardware and the swivel mounts etc are all easy to find on the internet in bulk and pretty cheap too.
so don't hesitate to make your own. or modify a sling you buy.
