So I got around to TIG welding up a barrel band sling swivel. It's not done yet but it is made from a 1" steel bushing and a piece of 3/8" key stock. I originally tried it with a wedge key but it was too narrow and got crooked when I welded it so i went back to 3/8" square key stock.
I welded them together and then cut out the piece in the middle so the ends of my welds won't be part of the finished product. Here are some pics:
