Yeah, the 293 H-Mantel load is listed at just a hair under 2400 fps, about like my 286-grain handload--which is no doubt why it also regulates in my rifle. This is a little less than the .375 Flanged 300-grain load but not enough to matter in the real world.
If I were going to buy a double rifle with more power than the 9.3x74R or .375 Flanged, I'd probably go with the .450/.400 3". In fact I've twice come very close to buying one, and did own a Ruger No. 1 .450/.400 for a while. It's easy to load for, brass and bullets are relatively easy to buy these days, and doesn't kick any more than a .375 H&H. And you've got the real ballistic advantage of a 400-grain, .40-caliber bullet.
