I need to start a topic on a 1863 1st conversion 50-70 Sharps I purchased a few weeks ago, it has me fired up (pun intended) about shooting it. 

But, more importantly for now, my quest for 50-70 brass has a happy ending. I've been on the Starline list for about 2.5 years, give or take a month or two. My son and his wife are stationed at Whiteman AFB, so I even stopped by Starline in person to inquire about 50-70 brass to no avail. I did purchase a few things at Sierra Bullets,  which is next door to Starline. 

After some research, I found this forum and read about turning 32ga shotgun brass into 50-70. I did contact a member for a source of brass and he got me started with a link to midwayusa.com. Once I received the brass it became obvious that it wasn't going to fit in my Forster case trimmer, no luck with the RCBS trimmer either. So, what to do? I contacted another forum member, to confirm an idea of mine would work. I was pleasantly surprised he was using the same 12.4mm piloted endmill bit that I planned to order. He said he drilled a hole in a wooden block and friction fit the case to the wood. Sounded like it would work fine, but didn't satisfy my need to make something on the lathe. I checked a piece of demilled 50 BMG brass to compare the size of the base of that case to a 50-70. The 50 BMG was larger in diameter and thicker. So, I decided to order a Lee 50 BMG case trimming base for $9 and some change at midwayusa.com. 

I recieved the Lee case trimming base for the 50 BMG, I quickly figured out it was going to need a shim. After looking in the standard washer bin, I had to run to the shop to dig through a drawer of misc. metric washer to find the thinnest washer that fit inside the Lee trimmer base. I then took the washer and put it the old Southbend 9" Lathe and cut the center to accept the 32ga shotgun brass. 

It took a couple of weeks for the piloted endmill to make it's way over from China. I would rather have USA made, but couldn't find one, not even used. Heck, I couldn't even find one in stock in the USA, so off to evil-bay the piloted endmill came in on Thursday. Right away I started to tinker with it all, put the Lee case trimmer base in the cordless drill. Used a cutoff wheel in the cordless mini grinder to make quick work of the bulk of the brass to be removed. Next was the piloted endmill, it finish trimmed the brass really well. One done, 24 more to go. Just waiting on a free evening to finish the rest. 

art_ruggiero wrote on Mar 17^th, 2025 at 12:29pm:

Yes they are great, buy a couple extra blades and make up some wood cradles to hold the brass. Make one for each case length you plan on cutting, maybe .020" over trim length. Also there are some 3d printed cradles on eBay in the calibers we shoot.

Wilson case holders work perfectly as the cut is perpendicular to the centerline and holds the case away from fingers etc. Not a great expense, and in my case have one for most common/uncommon cartridges.