Missed a very obvious one. Probably the major used one.

My list.

9.3x74R - an excellent driven game and running medium game cartridge. And will work on big and dangerous game even if minimal. A big advantage is rifles can be lighter and cheaper. Recoil is also very managable.

.375 H&H Flanged - slightly more powerful than the 9.3mm and far less common. The ,375 is usually a step up in heavier and larger double rifle models. I would love a modern scoped double rifle in .375 Flanged as my allround world hunting rifle for everything.

.400's - .408 to .411 calibre. Getting to be the best buffalo rifle calibres. .400 3 inch. And others. Still manageable recoil for many. And reasonably mild.

Slightly a step up in velocity and recoil, the new .416 No.2 Rigby and .500/416 NE. I think the first will be a great new contender for sales if other makers pick it up. These rifles do have extra velocity so increased recoil. And heavier rifles.

One reason perhaps the .500/416 never took off, applies to the .416 No.2 Rigby as well, is if the recoil is similar to the .450 NE, why not just use a .450 NE?

I came to this conclusion re the .500/416. And also consideration of the hot .375 Verney-Carron, vs the .375 Flanged. Double rifles aren't hotshot long range shooting rifles, so in my opinion, go up a calibre, a wider heavier bullet, but slower and also more effective. Or a lower recoiling cartridge in a more handy, lighter rifle.

Then we start to get to the stopper rifles. The .450's. The .450 NE's. And .470's, the most common new rifle DR choice, probably after the 9.3mm. The .475 etc. Shooting 480 to 500 gr projectiles at similar velocities.

Then the real stopper rifle choices. The .500 NE. And .577 NE. If you want a rifle for elephant up close, and especially in thick jess or forest. Wounded buffalo. Even lions "boiling" out of the bush, these are the ones you want your "gunbearer" to have close at hand. Heavier rifles, and hit hard at both ends.

Some might include the .600 NE, but I think they are very rare.

other than the 9.3x74R and the .470 NE, I wonder what are the most sold rifles, and also the most sold ammunition and components for DR cartridges? Particularly the medium calibre choices? Perhaps the 7x65R? 8x57RS mm?