I recently got a combination gun, the bottom barrel of which is 8x57JRS. For other people loading 8x57JRS, how are you trimming your brass? I think the Lee Zip Trim system will work, but I am not sure which case holder will work. A trim die would work. I have a Giraud that I could set up also. I also have a Forstner that I may be able to use.

Buy on e of these
WFT

Get the one with replaceable calibers so you can trim different cases. This is an awesome trimmer!

A good friend of mine loads for her 8x57JRS. She's using a Lyman trimming tool with the universal shellholder. Works a treat. Be sure to use the .323" pilot

Yep; I use Lyman universal shell holder type. One for a 444 Marlin might work; I have not tried this but I can if you want me to.

A Forster with the right pilot and collet will trim about any thing.
If you use one of the Lee Hand gadgets a .303. .44 Mag or .444 Marlin will probably work.

CDD,

Lee's Case Length Gauge works perfet - I use the one for an 8x57 Mauser for length

http://leeprecision.com/gage-holder-8x57-mauser.html

and their 3 Jaw Chuck (fits pretty much any case)

http://leeprecision.com/3-jaw-chuck.html

with their Case Spinner Stud in an electric screwdriver

http://leeprecision.com/case-spinner-stud.html

Lee will also will make custom Case Length Gauges - they made one for me in 9.3x72R & 9.3x74R (although the 9.3x74R is now a standard SKU).

Once you have the 3 Jaw Chuck w/Case Spinner Stud you can almost control your own destiny; I've added spacers to the cutters and made all sorts of specialty trimmers, like using a 22-250 Remington, adding spacers to the cutter stud to make the correct length for a 5.6x50R.

Good Luck