read the ingredients on the can, if it says it contains nitrocellulose, its a single based powder, the extreme powders and IMR 4350 are single based, the extreme bit is a marketing technique by hodgdon, if it says it contains nitrocellulose and nitroglycerine it is a double based powder and will be more temp sensitive than the singlebased powders.
temp sensitivity can be overcome though, just work up summer and winter loads and use them accordingly, if your rifle likes x-brand of bullet at 3100 fps, it doesn't care how much powder it takes to get it there due to the tempatures.
RR