Originally Posted by
Blackwater
As I understand it, and there are many stories and theories, the original cap n' ball revolvers were mostly ".36 caliber," with groove diameters of near .360". They shot round balls of .380" diameter, but the guns were called "36 caliber." Then, when we changed over to brass cartridges rather than loose powder and caps, the barrels were used as is, and the bullet size reduced to match the barrels. They no longer had to be larger than the groove diameter to shoot accurately. Somehow, and I don't recall how, they began calling them "38's," because the old balls had been .380 cal. in the cap n' ball guns. It's pretty confusing, and as with many historical things, it's very hard to know what the real story is, but I've seen it, and can't remember. That's what I remember of it, anyway.