Speaking of Kerr slings, here's a rare bird. A Kerr sling made of leather. As far as I know, there are only two known so far. This one I have and one owned by Hayes O.
We feel they are the first pattern Kerr slings and were made in leather following the norm of the time of using leather for slings.
I just measured the length of it after reading this post and found it's close to the 1917 Enfield sling size with the long piece a tad over 54 inches long, the short piece a little over 16 inches.
This opens up the possibility that having basically the same measurements as the Enfield slings, it could have been originally designed/made for the Enfield in leather at first for the Enfield when the US adopted that rifle. Later changing the sling to canvas.
If this is the case, it could mean that the Kerr sling was first made for the Enfield and later shortened and adoptd for the Springfield also. Maybe, who knows? Ray