nonalien1 wrote:
I ain't Arch but to answer your question American ammo is usually measured in inches . A 30-30 for example is .30 of an inch across. The other 30 used to refer to grains of powder.
A Desert Eagle .50 is half an inch across, but don't get to hung up by the numbers . A 38 special and a .357 magnum have the same diameter (.355) but a different size cartridge.
Hope this helps.