newer powders-higher velocity?

[wildcat westerner]

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.

 

[BigSkyGP]

I would look at a few things. I would look at a burn chart of burn rates. I would look at .30 cal cases of similar case volume for powder, and note the recommended charges, compared to what your current powder and charge are. Use the data from the other similar case volumes for powders that tend to exceed retumbo.

You have your past results to compare. And you should be able to draw new conclusions, for new powder.