[imardmd1]

It is simple. The brass which holds the 0.357" bullet is 0.375" O. D., and the chamber is then ~0.38". So the .38 is identified with the brass size.

Just measured mine. I have a Colt Commando Special, 6 rounds in the cylinder, same configuration as the Colt Detective Special.

[Inyo-Mono]

Which is pretty much what I said in my post #27.