DonD and everyone else, check out the Ching sling. Gives you the bicep-replacement support of the loop used in the leather M1907 (Turner competition type) and the GI cloth web sling, with the acquisition speed of the motion used to get into the hasty sling (arm through, around the sling, then hand through). Much faster than the military loop slings to get into and much more support and steadiness than just hasty with a carry strap. Got 'em on all my hunting rifles and you can sling up in a solid, weight-supporting loop in less time than it takes to go from standing to sitting.
As far as carrying, the Ching is just a 1" wide strap up front, though you can hand-make one at 1 1/4" using that width QD swivel. Not some AR CQB tacticool thing, just conventional shoulder carry.