Tim, the 7.62x39 will take about a full case of WC 680 under a 159 grain bullet. .30 Carbine case has about half the capacity, and I don't see how you can get enough 680 in it to hurt anything. I'd start there at about 10 grains. Once I had a handle on how 680 behaves, I'd use that info to work with other powders in the same class.