378 Weatherby with hot speed light bullets

[Bob B.]

Looking for load data to push Speer 235 bullets as fast as possible out of my 378 Weatherby mag. Anyone got anything ?
Thanks, Bob

 

[wboggs]

The traditional powder was imr 4350 for lighter bullets and h4831 for the 300's.
Loaddata will have loads for the old speer 235's. Most people loaded them for a practice load at lower velocities and did not try to max them out.

 

[Bob B.]

The traditional powder was imr 4350 for lighter bullets and h4831 for the 300's.
Loaddata will have loads for the old speer 235's. Most people loaded them for a practice load at lower velocities and did not try to max them out.

Hi, good to hear from you again. I already have hot loads for Lehigh 175 and 185 bullets. But the Speers are possibly the best bullet for the money for any 375. Sierra 200 grain is devastating out of the H&H on deer. Just want to see what others have achieved out the 378. Speer told me they haven't tested it past 3000 fps, but didn't tell me not to try. If not for experimintation we'd all be shooting 50 caliber muzzle loaders ....

 

[wboggs]

You can get about 3200-3300 from a full power load. Would likely blow up like a bomb at close range at that velocity.Go ahead and try them, just don't expect much penetration or accuracy since they jump a lot in a normal wby freebore.

 

[Dusty Stevens]

You can push a bullet too fast. The cheaper they are, the lower that speed is