I have not hunted with the factory loaded stuff, but I use a lot of PPU brass, its the oldest firearm ammuntion manufacturing co. in the world.Its good stuff..The bullets would probably be on par with WW power points or Rem corelokts in that they are not bonded core as far as I know, so I would expect them to penetrate well and expand. Weight would depend on game hunted, 300 gr. for buffalo solids and SP...I doubt that fragmentation bulletrs would be in the scenario for the .375 H&H, Its a large animal caliber..Velocity will be in the 2500 FPS give or take 100 FPS with the 300 gr., 2600 with the 270 gr. Typical factory .375 ammo..Accuracy is totally dependent on your particular rifle, a rifle is an inity unto itself, what is accurate in one .375 or any caliber is inconclusive to any other rifle of the same caliber...
Having not used this particular ammo in my .375, but been using the caliber for 60 years and shot a high number of bufflao, I wouldn't hesitate to use PPU ammo for Buffalo..Id bet dollars to donuts I pretty close to spot on answering your post.
