Some of the very early Colts were chambered in .32 Long or Short Colt.
It`s very close to .32 S&W. One has a slightly larger diameter than the other, but off the top of my head I can`t remember which. Think the .32 Colt is bigger, but would have to dig out some of the ammo to measure to be sure.

This little Colt New Pocket is chambered in .32 Long Colt. Made 1899.
.32 Long Colt is real hard to find, but it eats .32 Short just fine.
I lucked out and found 3 boxes of .32 Short Colt cheap at an auction a few years ago. Allowed me to play a little with this little critter.