Lonnie, you are sure right about the 30 Luger, most measure .309-.310" but getting those diameter bullets are damn near impossible unless you cast and size them or take the .311" or .312" jacketed bullets and size them down to .3095+-" one thousands at a time (Hugh Clark's trick) The accuracy of a .308" diameter bullet in the 30 Luger barrel CAN be phenomenal, so I dont bother with the sizing stuff. See attached picture of the 0.8" group I fired with the .308" Hornady bullets! I doubt I could have done any better with a .310" bullet. ~Thor~
http://boards.rennlist.com/upload/30LugerTarget.jpg