Hello, Ten years ago I designed a 30 caliber wildcat based on the RWS 9.3 x64 brass. With its rim reduced to '06 dimensions it was like a .284 on steroids being 1/2" longer. I was able to duplicate .300 Weatherby published ballistics with Nosler 180 gr. accubond bullets with Retumbo powder. Now, since I have retired to New Mexico I am completing a hunting rifle in this caliber and have been told that there are several newer powders presently being made which may be superior to the load I developed for this cartridge of 79 grains of Retumbo. It was a pleasure developing this cartridge because it developed those velocities of 3,200 fps with no free bore, unlike the Weatherby cartridges and I also could place four in the magazine, just like an '06 cartridge. Thanks in advance for your insights in this matter. Gene S.