What's the best or easiet way to thin the rim? I have already turned the rims to the required smaller diameter but still need to thin them. They are currently .065" and need to be .055" or they won't fit into the shell holder.

I used a mill and 1/2" collet to hold the cases worked well enough and its easy to measure the diameter. Measuring the thickness not so.

Thanks,

M

I used a collet and made a tool with a hook to reach around and thin the rim on 30/40 Krags so they could become 8X57 JR's. Of course this was done in a lathe.

My problem is I don't have collets for my lathe. The 4 jaw just isn't delicate enough on the old south bend.

I'll probably have to just continue to do this in my mill. I'll fashion a tool like you said and hold it in the vice. It's just so dadgum slow!

If you have a three jaw chuck for the lathe you might put the collet in it and tighten it up. I tried my .480" collet and it held an 06 sized case fine.

If you have a lathe you can thin rims the following way. Deprime your brass then put a piece of steel in the 3 jaw chuck and turn a small stub on the bar that is a tight fit in the primer pocket. Leave a shoulder behind the stub to index the case on. You can then press the cases on to the stub and run a live center into the case mouth. Since you are indexing on the base of the case your rims will all be of uniform thickness. If you take small cuts you will have no problems with the cases slipping on the stub in the primer pocket. Have used this method to correct many Bertram cases that were out of spec. Really lousy brass.
Good luck.

Bob G,

That's a great idea. I'll have to try it this week.

I found a mini lathe 3 jaw that will fit in a sleeve, but your idea puts the rim facing away from the chuck giving plenty of room.

Thanks,

M