I have a ruger #1 in 375 h&h. I shoot it often and enjoy the gun but have recently heard of serval improved versions which might produce 300 win mag ballistics out to 500 yards. This is my one gun I use on everything from our small arizona whitetails to Alaska Moose. Does anyone have any data or suggestions for the various improved versions?

P.O. Ackley's book, Handbook for Shooters and Reloaders, Vol #1 shows several improved versions of the 375 H&H cartridge. The .375 ICL Kodiak, the .375 Mashburn Mag, the .375 Weatherby, the .375 Mag Ack Imp and even the .378 Weatherby (actually, an improved version of the .375 H&H).

The .378 Weatherby has the highest powder capacity and the highest velocity rating, followed by the Mashburn and then the Ackley Improved.

RCBS or Redding would be able to provide reloading dies for the Mashburn or the Ackley Improved versions - kinda pricey, though! The .378 Weatherby should be stock.

Best bet might be the 375 Weatherby wich is just a 375 H&H improved, didn't they just start rechambering this in factory guns and putting out ammo? The 378 Weatherby is much larger than the 375 H&H case and has the recoil to match.

Garth - The 375 Weatherby was a predecessor of the 378 Weatherby. You're right it has a much larger head and body dia, too. They fairly recently reintroduced the 375 Wea.

Gene Dip

I have a ruger #1 in 375 h&h. I shoot it often and enjoy the gun but have recently heard of serval improved versions which might produce 300 win mag ballistics out to 500 yards. This is my one gun I use on everything from our small arizona whitetails to Alaska Moose. Does anyone have any data or suggestions for the various improved versions?
Robin, I would also vote for the 375 Weatherby. Dies, load data and everything is more readily available than the other improved versions. It's a "popular" round here in Alaska.