Kachok, if you have a typical 24" barreled 270 Winchester, pretty much all of the slowest burning rifle powders will get you there, or very close to it. Magpro is definitely one of them. I have that powder, but no longer have a chronograph to test it. The WWII surplus powder that was repackaged by Hodgdon as H-4831 is another as well, as is IMR 7828, Reloder 22, etc. I've played with all of these and more. But the thing is, if we're talking about a scoped, bolt-action, long-range-capable hunting rifle, then accuracy at 100 yards means nothing. It's at 300 or more yards where we need to be doing our accuracy tests. My pet load is sub M.O.A. for 5 shots at 300. I wouldn't care if I had to drop down to a lower velocity to get it. Most of the loads that look most promising at 100 yards in my rifle deliver 12" to 18" 5 shot groups at 300 yards. But the magic formula for this rifle uses Federal brass, Nosler 150 grain partitions, CCI-200 primers, and a fairly maximum charge of the long-discontinued, but fabulous, Norma N-205 powder. Forgive me for not say exactly how much of this wonder powder to use, because it is not a starting charge. How do you like your 270 WSM? I think that is the most interesting of the WSM line of cartridges. Is it a Model 70? I know that this thread is supposed to be about the 264 Winchester and 7mm Remington magnums, primarily. So, circling back on track, I think those are both quite potent hunting calibers, and if anyone has one that works well for them, they should stick with it. Sure, the magnums are sacrificing magazine capacity, but how many shots do you really need? Heck, my brother likes magnum cartridges in the Browning falling-block single shot rifles, and he's got a method where he is impressively fast on repeat shots. But clearly, the 264 Winchester and 7mm Remington magnums have potent rivals. And some of those that come to my mind, that I consider to be in the same class, performance-wise, include the 257, 270, and 7mm Weatherby's, along with similar WSM cartridges, the obsolete, but under-rated 6.5mm Remington Magnum, the wildcat 6.5-'06, the 6.5mm Norma, the 280 Remington and 284 Winchester, and perhaps best of all, the legendary 270 Winchester.