I had always believed that the caliber of a gun was the inside diameter of the barrel. Assuming I am correct (am I?) then shouldn't .38 and .380 be "close"? If I remember from high school math, the latter simply implies a greater degree of precision. IOW, a .38 caliber really could be anything from .376 to .384, while .380 caliber has smaller variance--.3796 to .3804? However, the attendant at a local range said that .38 refers to revolvers while .380 refers to pistols (?) Thanks.