You need a metal lathe and a 30 carbine chamber reamer to create that type of gauge but its easy. You basically are making a barrel stub with the chamber deeper to exact spec. The reamers can be found at brownells. Ive made ones for 9mm luger to catch the reloads that ended up with Makarov cases but its too time consuming to try to gauge all the rounds when I just made 1000 or more.