The 35 Whelen was the first of  3 (three) efforts by Griffin and Howe to produce a cartridge that would meet this ideal. All were in 35 caliber. The 35 Whelen is simply the 30-06 necked up to 35 caliber  and it’s about as easy to form from '06 brass as is the 270. Later, an "improved" version of the 35 Whelen, with venturi shoulders like Weatherby cartridges, was made up, but it never caught on. The 35 Whelen, now available in several factory rounds, and factory chambered in several different rifles (although some gunsmiths still sell properly formed brass for it) has racked up a tremendous record all over the world, rivaling the 375 Holland and Holland in its effectiveness. It was originally designed, partially, as a substitute for the 375 H & H, since rifles for it could be made up using inexpensive 30-06 actions rather than costly magnum-length Mauser Actions It has killed, with aplomb and efficiency, all of the trophy animals in the world, with the possible exception of the “Big Three” (elephant, rhinoceros, and cape buffalo.) It can be loaded down to 35 Remington speeds for light recoil and pot-shooting, or loaded up to provide terrific stopping power--more than should ever be needed by a competent rifleman facing American big game. Although not legal in certain parts of Africa for dangerous game (some countries require that rifles of at least 375 or 400 caliber be used,) solid nose bullets are available so that, in a pinch, it would probably serve. It is easy to rebarrel an action to this cartridge-- it does not even require opening up the bolt face or free-boring; the rimless brass for it, as with the 358, is cheaper and easier to manufacture than the belted brass necessary for the 350 Remington, 35 Griffin and Howe (or Holland and Holland, as it is sometimes known) and 358 Norma Magnum. There is still a great future awaiting the 35 Whelen and, now that the 22-250 has been legitimized, perhaps we can hope that the 35 Whelen will meet the same good fortune.