OK--just went out and tried it. Full moon clips that I use in
my S&W 625, loaded with inert rounds.
1917 S&W 45 ACP----they fit fine.
I don't have a 1917 Colt, but I tried it in
a 1913 era Colt New Service 38-40. They
started in, and it looks like they would work
just fine in a 1917 45 ACP Colt.