When I decided to go down the .375 road, there were 3 rounds I considered, the H&H, the Ultramag, and the .378 Weatherby, the .375 Ruger had yet to make it to the drawing board. I already knew whichever one I chose would be chambered in a Brno 602. First off, I discounted the H&H, I wanted to have a short barrel rifle, with long barrel H&H ballistics, which could be easily achieved by choosing a cartridge with greater powder capacity. True, with normal weight bullets, the difference is only 50-75 fps, but with 350 and 380 gr bullets, the difference is more like 150 fps. It was a more difficult decision, but I finally decided to dismiss the .378 Weatherby. These big cartridges eat up magazine capacity, taking an unmodified 602 down to 3, and while still recovering from a love affair with the .416 Rigby which at the time cost nearly $200 for 50 brass by the time they made it to my mail box, I wasn't anxious to go down the expensive brass road again. As a result I chose the .375 Ultra. It comfortably holds 100 grs of H-4831 with a 300 gr bullet, it drives a 380 gr bullet at 2350 fps from a 20" barrel, and the 602 magazine holds 4, actually it hold 5, but with 5 its too tight for reliable cycling. The down side is the rebated rim of the Ultra cartridge; contact with the bolt face is minimum, but that said, I never experienced a failure to feed due to this "perceived" problem. Was I going through this exercise today, it would be difficult not to recognize the benefits of the .375 Ruger, although I prefer the original Alaskan rifle to the offerings today.
I figured I had enough power with a mild load for North America.
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in another moment of weakness and after reading P.O.Ackley's info on the 375, I acquired a 375 Chatfield Taylor. 
