Bill,
I believe you can shoot 32 long or short Colt, if you can find it. The original cartridge had a heeled, outside lubricated bullet .313" in dia. Later ammo had a .298"inside lubricated bullet, .298" in dia, but intended to expand for a closer fit to the barrel. They didn't expand very well, but the 300 bullet is only .300, which is close enough. The 32 S&W long or short will not work. The head diameter of 22 Hornet is too close to .300 to make an insert practical. I think a 22 LR insert (w/o extractor) may be possible, but the barrel will be very thin.
Mike
