Thread: 257 Weatherby Magnum

A mate has asked me to help set up reloads for one.

I'm looking for any tips or advice for this cartridge because I haven't reloaded for a belted magnum before.



I understand that the first thing is to set up the sizing die close top the length of the fired case so you only bump the shoulder back .003" approx. (same as all cartridges). The Weatherby doesn't seem to have an official datum on the shoulder, just specs for the end of the case body and the start of the neck. Would it be OK if I just use my 0.400" collar and use a length from case base to that ? Or does it have to be .3963" x 2.117- ? I see the chamber spec uses a 0.4050" diameter.

I think the rifle is a Weatherby Mark V .
I'll be using a co-ax press and Redding dies.
I'm used to loading for 7mm08 and .303.

I haven't got a Weatherby case holder for priming so might just have to use the priming facility on the press ?

I'll ask more questions but first see what comes back for those two.

What else should I look out for ?

Many thanks in advance.