Loading equpment for the 338-378 Weatherby


Active Member
Jun 10, 2013
I bought a 338-378 Weatherby Accumark last October for elk season. Shot my elk with 250 gr partitions in factory Weatherby ammo at 550 yds. I would like to shoot a more efficient bullet and am looking at the 250-300 gr Bergers and AMAX's. I have been loading for other calibers but would really like to get the most out of this rifle out to at least 1000yds and more when I can range accurately past that.

What type of die should I be getting for this? Neck size and bump shoulder ever couple of firings? Use the full length die to bump shoulder and neck size or completely full length size?

I have read here that a lot of people are using bushing dies to size the necks. I don't see any offered for the Weatherby, but could get some custom made if this would be the best route.

Are there any other tips or tricks that I should be doing to get the best out of this rifle.

Thanks for the help



Well-Known Member
Apr 28, 2013
tucson az
Thomas, I looked at that too, and found nothing, but there is another site called weatherby nation, and lots of information for those cartridges. Several people post there as well as here. I neck size only with the F L sizer die backed off a bit, and when they get hard to close on, I run the die back down to full length size the case. Seem to be doing all rite on case life like that, too. On the 7th go around. Course, this might be it for them, too! Really like that monster, hope youdo too. Gregg