There are videos on youtube showing how to do this. I bought a cheap, as in under $30, cut off saw from harbor freight. Tiny little thing. Then I, tinkerer that I am, fabbed up a fixture to position the 223/5.56 brass and just do a quick cutoff on it. One pass through the die, trim to length, and have fun. Mine is an AR, but the brass doesn't care what it winds up in. It is a bit slow, but I tinker at work, so I usually do a hundred piece batch, one step each night til it's ready. Then I start on another hundred. I have about 500 worked up and ready, another 500 to do in the next 2 weeks or so.