Saw an Dan Wesson shooter at the range, he had a .375 "super magnum" gun.

Monster rounds, silly recoil.

Says he had to spend a few months finding brass and bullets that would work with the little published data.  He had some real 375 brass, and some that was formed from cut down 30-30 winchester casings.   He let me shoot one round, and its a hell of  a load.   .375 caliber flat nose 200 grainer.

I guess they were developed for long range steel shooting.  

Hell of a thump in the recoil area, though!