Hey it’s a question I can answer! My camera’s dead tonight; I can try to add some pics tomorrow if that would help. So here’s the breakdown of a M1907 sling. I took specs from one of the earliest makers, Rock Island Armory, and measuring my own Turner/Brownells Biothane sling.
Long loop- 1 each, leather, 10oz full grain, 1 ¼ inches wide by 56 inches long, edge creased. One end has the double hook, or “frog”, triple riveted to it. The other end is rounded. It has sixteen (16) double rows of 3/16 inch holes. There are 32 total, starting 2 inches from hook end. They’re punched 1 1/8 inches center to center which is also about 1 inch edge to edge.
Short loop- 1 each, leather, 10oz full grain, 1 ¼ inches wide by 27 inches long, edge creased. One end has the double hook, or “frog”, triple riveted to it. The other end has a 1.25 inch welded rectangular ring stitched in place. The ring is located 3 inches from the end and the stitching is in both creased channels, two rows each 2 5/8 inches long with one stitch inboard and doubled back one stitch. It has fifteen (15) double rows of 3/16 inch holes. There are 30 total, starting on the ring end, 1/4 inch from the end of the leather where it’s stitched down, or measured 3 ¼ inches from the end. They’re punched 1 1/8 inches center to center which is also about 1 inch edge to edge.
Keepers- 2 each, leather 10oz full grain, 7/8 inch by 6 inches, edge creased, ends skived 1 inch, glued and stitched. Overall circumference is 4 inches, with skiving overlapped. The stitching is in both creased channels, two rows each 7/8 inch long.
Hooks and ring are Parkerized steel (earliest were blackened brass) and rivets are brass.
Hope this helps. Here’s some detail pics I swiped off the web.
Ring end
Hooks
Keepers