I have a remington 700 in 375 rem ultra mag and it works fine. I don't think you will want too shoot or can match the 378 weatherby performance in a light gun.I have not seen many reloading recipies to get 6,000 ft. lbs out of the 375 rum. The factory loads at 5072 ft. lbs in a 7 1/2 lb rifle are fairly stout,at least for me anyway.