For the M1917, the Kerr sling long piece should be about 54 inches long, the short piece at 16 inches.
For the M1903, the long length is 48 inches and the short length around 14-1/2 inches.
For the Thompson, the long piece is 40 inches long.

The Kragicon and TD slings I have with a single brass fastener are 66-68" long. Ray