Sure, 10 mm=.40in. But in the same manner, 9 mm=.357 in. We all know how to do math, but we also know that even though their diameters are the same, they are still different calibers. The poster asked for .40 cal, not .40in diameter. While your suggestion of 10mm may be useful to him, please don't try to argue that .40 S&W and 10mm are the same.Originally posted by mavracer:
OP said .40cal pistol and last I checked 10mm=.40
actually 10mm and the 40 S&W are both 40 caliber so is the 38-40 revolver round.but this is the auto forum and I don't know of any 38-40 autos.BTW 9mm = .355 not .357.Sure, 10 mm=.40in. But in the same manner, 9 mm=.357 in. We all know how to do math, but we also know that even though their diameters are the same, they are still different calibers. The poster asked for .40 cal, not .40in diameter. While your suggestion of 10mm may be useful to him, please don't try to argue that .40 S&W and 10mm are the same.
so 10mm is indeed 40calCalibre (or caliber) :2. Firearms: The approximate diameter of the circle formed by the tops of the lands of a rifled barrel.