You certainly make a lot of ASSUMPTIONS. We all know how that ends. I am an old man and have found assumptions in general to be a pursuit of dubious utilitarian value, and an absolutely deplorable social habit.A 9.3x74R is a fine caliber but not exactly a "classic" African round. It isn't even legal for dangerous game in a number of places in Africa which I assume is the intended use of the OP's eventual rifle. It was and still is a popular European caliber for driven boar. red stag, and Nordic moose.
Unless one's liability insurance is substantial, I don't believe I would recommend rechambering a .375 Winchester anything to 375 H&H flanged. The 375 W has a case length of 2.05 inches and a .375 flanged is nearly a full half inch longer. So much chamber metal would have to be removed to have potentially created a hand grenade inches from one's face. I can't imagine how thin that shoulder would mike.
1. You assume the OP wants another DG caliber when he already states he owns medium bore and big bore DG rifles, and wants a double rifle to "complement", not replace, those. You assume a lot more than that.
2. You assume I am recommending 9.3x74R to the OP. I just stated that is the choice I made and they make other calibers in the same rifle, which I also mentioned. I was recommending consideration of a brand and type on rifle, not caliber.
3. You assume your opinion of "classic" African rounds is valid or even germane. BTW 9.3x74R has been in use constantly for over 100 years IN AFRICA in German colonies, and predates the 9.3x62 and other 9.3's which have also been in service IN AFRICA for over 100 years. What criteria do you use for "classic"? 9.3's have probably been used 1000 percent more than the 416 Rigby over the last 100 years IN AFRICA, on game dangerous and otherwise. Does that make the 9.3x74R 10 times more "classic" than the 416 Rigby?
4. You assume the 375 Win barrel taper was cut in close tolerance to the chamber and might therefore be unsafe in longer cartridge, or that I was somehow unaware of cartridge lengths or safety issues when considering firearms modification.
5. You assume I didn't have a competent gunsmith, with decades of experience specifically on double rifles, doing the work who checked safety issues and crucial measurements first, as any competent gunsmith would.
The one true FACT you stated was in your final sentence, "I can't imagine ...". I would remind you that the endless volumes of things you cannot imagine are where your assumptions come from. I have endless volumes of things I cannot imagine as well, as we all do. I just don't go around responding to other people based on those things. Good luck with that.
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