|From Sarge & Gunowner|
When Holland and Holland brought out this cartridge in 1912 it was actually two cartridges. A belted magnum and a flanged (rimmed) magnum. The belted cartridge was for bolt action rifles and the flanged one for double and combination rifles. They did not bring these rounds out to compete with someone elses rounds as at that time there was no cartridge like them anywhere. They were the first! The closest competitors and close means they were in the race but no could see them for the dust that the .375 kicked up, was the 450/500 flanged, the 404 Jeffery in bolt actions, smaller 350 Rigby magnum.
The .375 offered flat trejectory (for the time) and plenty of bullet weight for punch, and a reputation for outstanding performance in the field. It was obvious that the cartridge was designed for African game as the English game was all small stuff with even their Roe Deer ( kind of an elk) was small enough to put down with a British 303.
Alaskans found this cartridge and took it to their heart. Any thing that will stop a 1000 lb. moose or a 600 lb bear is a good gun up in that country. What kind of power does it have? How about a 300 gr soft point at 2620 fps MV. Doesn't sound like much with our supersonic bullets now a days but take a look at the energy at the muzzle. 4115 ft lb. And the beast takes 80 to 83 grains of powder in that big case. What a buddy gun that would be!