Trimming 50/70 brass

[mm1ut1]

I'm cutting down 50/70 brass to fit a one off rifle and need help finding tools to trim the final few thousandths. Any suggestions would be greatly appreciated ! Thanks !

[Gar]

I use my Lyman Universal Case Trimmer to trim my 12.7x44R (.50) cases. I just turned a .50 pilot from a piece of 1/2 round steel stock.

[EDG]

Wilson makes a 50 caliber cutter for their trimmers and they make a 50 cal BMG trimmer.
All you would need is the custom case holder made by Wilson.

Forster makes a Classic trimmer that might work for the 50-70 with the right collet and pilot.
You can also get a trim die from CH.

[reed1911]

I don't think the trim die will work since he needs to trim it shorter than 50-70 (at least as I read the post). You could turn a 50-70 trim die down (from the base) so the ram would push the brass out to the required amount and trim that way. Myself, I would simply make one, lots of different ways. How bout this, what tooling experience/shop experience do you have and what kind of trimming set-up do you use now?

[mm1ut1]

I'm cutting/trimming them to 1.161". I have a machinist with a well equipped shop to who is helping me with this project. Rather not pull him off other projects if I can help it.

[reed1911]

Okay, well if you have a hollow center cut mill that is 5/8 or so, you can make a short rod that will fit up in the mill and act as a stop, you'll just need to measure the depth of the hole and add the internal length of the brass for the proper length. That would be the fast and dirty approach. You can have him face off the bottom of a trim die the required amount to allow you to trim to the proper length. If you want a trim die, you can always have him chuck up a piece and make one, 7/8x14 threads, and heat treat it, or you may not even need that if you are only going to make a handful of brass. Let me know if those are options or not.

[EDG]

I'm cutting/trimming them to 1.161". I have a machinist with a well equipped shop to who is helping me with this project. Rather not pull him off other projects if I can help it.

Your machinist can make a plug to cut them off way faster than you can mess with them.

Machine a flat face slug and then bore a shallow recess the diameter of the rims with about .002 clearance.

Then put an extended blunt center in the live center. The blunt center should be about .505 dia.
Use it to push the case against the plug in the chuck. Hold the spinning case with force applied by the tail stock and part off with the left hand. He can probably do a case in 30 seconds once the plug is made.

[mm1ut1]

Got the cases cut on the lathe. Forster makes a case trimmer that will handle the short, fat cases. Thanks to all for advice/info !