I am finding it hard to get 100 or even 20 rounds of 300 Black Out. So I need to know the correct length to shorten the .223 Remington case before running it into the die? Can anyone outline their methods? I need the "cut to" length and if there is a max wall thickness to the neck? I can thin the neck if needed. Does anybody have all that data? I have once fired cases, mostly Federal. I don't think any military brass is in my stash. Thanks for your time and Be Well, Packy.

I have a form/file trim die if you want to borrow it Packy.

I usually cut where the body turns into the shoulder. Then run it into a 300 BO sizing die. Then I trim a bunch at a time with the LEE trimmer attach to a drill. Chamfer and it should be good to go.

There are plenty of you tube videos out there showing how it is done.

Thanks HB. I wasn't sure if you had to measure precisely or not. Be Well, Packy.

quote:

Originally posted by HARDBALLER:
I usually cut where the body turns into the shoulder. Then run it into a 300 BO sizing die. Then I trim a bunch at a time with the LEE trimmer attach to a drill. Chamfer and it should be good to go.

+1
I "trim" with a shop grinder to just longer than finished length (hint, use gloves), then run the slightly long case through the .300 BKOUT FL die (adjusted so that the shoulder is perfectly headspaced for my chamber as I'm using a bolt gun). Afterwards, trim to proper length with a case trimmer, then chamfer the necks. The only cases I've lost in this process have been a couple which I accidentally ground too short in the initial shortening. Case neck thickness has been fine without any need to thin.