To make 300 Blackout brass from 223, I use a miniature chop saw I got from Harbor Freight... The blades only come one way... little bit heavy in the tooth department, so you have to start really slow when you ease into the brass or BAM! and the teeth will throw it across the room. But, so long as you remember to start slow, it works a charm. That gets them trimmed down to a decent length, so then you can put them on the rotary trimmer for the next step. I made a little jig to clamp in place that cradles the brass so it'll cut at the right length. Hold it down with a couple fingers while cutting. It only takes a couple times of hitting it too quick with the blade to learn not to. It doesn't draw blood, but it sho' nuff hurts!
