A friend has a supply of BELL .577 basic brass. He wants to trim it to 577 NE 3". It looks about .10" too long. I suggested a hack saw.
Seriously, what's the best way to do this without involving a Machinist?
Thanks everyone.

I size them full length and trim them in a file trim die. Be careful when you size them as it is very easy to crush the thin Bell cylindrical brass. I’ve lost a few.

RC

.10" wouldn't bee to hard to take down with a belt sander.
May need to angle the table a slight bit to keep the mouth square as they do have a bit of taper.
If the basic brass is truly cylindrical then that is easier for sure.

Thanks to you both. The brass has some out of round mouths from handling.
I didn't think of a trim die. I believe his dies are CNH. I'll ask if it has one.

An easy way might be using a fine flat file.

You don’t need to remove much.

I don't know how others find using trim dies for large mouth cases but when I made one up to trim some of my 404 cases I found occasionally the file would grab and crush in the side of the case mouth. The 404 cases I have, Parker Hale, Kynoch and RWS all have quite thin brass at the mouth. As new RWS brass is 1mm shorter than standard I wanted to trim the PH and Kynoch to same length to make crimping easier.

I have since made up a 404 spigot for my rotary case trimmer so don't use the trim die any more.

I trimmed my BELL 577 cases with a tubing cutter. Very clean, very easy. I'm a plumber and so cutting brass, copper, etc is second nature.
My cutter is an Imperial Eastman 174F, but any copper cutter will work.