With chambers cut with the same leade and cartridges loaded to the same pressures the two are identical...........look at the 7mmRM and 7 Wby. I have the Wby on a Sako L61R that I cut from an H&H chamber with 24" barrel, but have yet to work up any loads for it. Neither has any advantage over the other, unless headstamps and SAAMI specs mean something to you. I fireformed 100 cases for it using a bunch or R-P cases I had in H&H, never lost a one and they popped out perfectly. Of all the Weatherby chambered rifles I have the only actual Weatherby gun is my 378 and the only Weatherby brass I use is for that 378, everything else I shoot in Weatherby chamberings I make brass for from some standard case and usually in W-W brass. Therefore it doesn't cost a penny more to shoot Weatherby chambered rifles than any other magnum cartridge.
As "elker" pointed out I do seem to have an affinity for Weatherby cartridges, if not their rifles, but it just worked out that way. I have never considered myself one of the Koolaid drinkers of Weatherby propaganda, it just seems that in my search for the ultimate ballistics in each caliber I worked with, I ended up with a Weatherby cartridge. We must also keep in mind that most of this cartridge testing and playing took place before the 404 based cartridges hit the scene, in fact I was playing with them too even before the Imperial Mags came out. I don't think anyone will disagree that the 257 Bee is the ultimate 25 cal, now there is the 6.5-300 Wby is certainly a contender, with brass being 1/4 the price of the Nosler. I also had a 7mm-300 Wby on a Ruger #1 with a 28" barrel, then the 300 Wby was the top of the heap, until I developed the 30-404 Imp long before Remington or Imperial Magnum did. But we didn't have the powders then to really turn it on like today. I was very disappointed with the 338 WM and used several of them a lot, but was astonished at the change of reaction on game when you added 300 fps in the 340 Wby. I haven't taken any game with my 2X 37 cal Wby offerings (375 and 378) or even worked up loads for them as I may hunt with them one day but maybe not given the successes I have had with my H&H on game needing this range of cartridge and caliber..........HHMM, well that is kinda a disjointed rambling.............
Gate.......you specifically stated in other threads that you were about to build or buy a 375 Wby until the Ruger arrived on the scene.