I'm getting the impression we're not on the same page.
I'm not saying that two different cartridges, even of similar capacity and performance potential, can't like different powders best.
What I am saying is that a particular cartridge, 7mm Rem. magnum for example, that finds RL22 to be a clear winner in a 26" barrel isn't going to suddenly like 4064 the best if you have that same barrel cut and crowned to 20" for some reason.
