All that stuff is fun .38-40 is actually .40, a .36 Navy is a .38 but a .38 special is almost a .36, a .41 Long Colt (depending on how you measure) is .38ish and on and on a 56-56 Spencer is neither .56 caliber nor 56 grains of black powder. The new 56-50 Spencers are .51 caliber ah well.