Just to squeeze the last drop of goodness out of this topic-- we might want to mention that bullet diameters and bore diameters and the names of their associated cartridges are not always the same, as you've just discovered. It all has to do with whether the cartridge bears the designation of the bore diameter measured at the lands or the grooves of the barrel. So you find some odd situations like the .38 special (named for the diameter of the bore measured at the grooves) and the .357 magnum (measured at the lands) using the same bullet diameters, which is .357" unless you use lead bullets which will be .001" larger.
The .38 came before the .357 and was based on the same bore as the .36 caliber pistols of Wild Bill's day.................then there are cartridges named after the bore AND powder charge or the bore and the year of acceptance by the military not to mention metric and.........................oops all the goodness is gone now.
