I have a custom Brno 602 chambered for the .375 Ultra. I chose the chambering so that I could achieve .375 H&H long barrel velocities from a short barrel, and in this I prevailed. However, I was made aware of another fellow who cut down his Brno 602 .375 H&H with a loss of only 40 FPS. That said, it is clear that the additional 50 FPS I gained does not justify the additional cost of powder and brass.

While I am quite happy with my rifle, I would be very surprised if you actually realized a 200 FPS advantage over the H&H. If you want a high speed .375 perhaps you are a candidate for a .378 Weatherby. I also considered this cartridge and rejected it due to the cost of brass. I had a .416 Rigby which proved expensive to feed, so I did not wish to repeat that situation