Robinson no longer stocks that sling, it needs a sling with a snapple hook, and it should look like it belongs. As this rifle is "new" and really has no historic value, I could do just about anything I wanted. How about an assault sling? You know, the three point thing that is all the rage for "tough operators" Nope, never needed one.
I went down to one of our local "surplus stores" and bought four feet of 1 1/2 inch nylon strap, two black buckles, and a snapple hook. Cost me $4.05, fits the stocks sling swivel perfectly, and has plenty of adjustment.
I probably could have gone with five feet, but this works fine.