04-26-2009, 09:14 AM
Join Date: Dec 2002
Location: Jefferson Parish (via N.O.)
You'd really have to work at it and would expect to lose a few along the way.
this is NOT a recommendation...just what some of us had to do back when we either had no money, cases were hard to come by, or both....but those dasy can come upon us again, so I'll post it anyway.
Strip the .257 die of it's decapping assembly...make it a hollow tube.
Use good case lube (Imprerial Die Wax)
Screw the die up in the press until it just barely touches a .270 case when the ram is up.
Screw the die down 1/2 turn.
Run all the .270 cases though the die
Turn the die down 1/2 turn and run all the .270 cases through
Keep doing that last step until they are full sized.
Neck ream or outside turn to standard .257 thickness
Reinstall the decapper
Resize them as if they were .257 cases.
May still find that they WON'T chamber. Brass springs back a bit, and the thick brass of the shoulder springs back more than the thin neck...may find that the cases just barely won't chamber. One solution is to grind/stone down the top of a shell holder (always work on the cheap part when you have a choice). that would let you turn the die down a little more...which would let you set the sprung-back shoulder back just a little bit more....it's a size-n-try kind of arrangement.
(NOte: HIDE THAT SHELL HOLDER...it's going to get you in trouble some day.)
Cases would probably need annelaing at this point, as the now shorter cases have their necks in an area of the .270case that wasn't designed to be a neck.
When you're all done, will need to get the volume of your new made cases....compare it to the volume of "real" .257 cases...reduce loads based on the percentage of difference.
Or you can just buy some .257 cases.
Last edited by ribbonstone; 04-26-2009 at 09:16 AM.