Larry Vickers is a retired US Army spec ops soldier(CAG/Delta Force/SFOD-Delta). He is also a well known pistolsmith(1911a1 .45acp).
His tactical rifle sling is a tad pricey but I like the pad type design.
Im not a huge fan of bungee or elastic anything on a weapon. Tropic or humid environments with high temps seem to warp/wear out these materials quickly.
As I stated, if speed/tactical applications are a main concern, look for a rig you can draw quickly or switch firing hands with rapidly.
If you just want a basic rifle sling or something milspec that shouldn't be difficult to buy either.
Clyde