Aviator,
"Mule Deer can you elaborate on the caliber specific powders?"--
A good example is Vihtavuori's N555, which is between their N550 and N560 in burn-rate. The specific application is the 6.5 Creedmoor with bullet from around 130 grains up. I recently tried it in my Bergara Ridge, which had shot pretty well but not exceptionally with the new 135-grain Hornady A-Tip with a couple of popular 6.5 CM powders. I didn't really work up a load with N555, just used the max charge VV lists for the 136-grain Scenar, with the A-Tip seated the same in the same brass, with the same primer. Three, 3-shot groups at 100 yards averaged .37 inch at around 2760 fps, better than the results with any of the other powders. A little tweaking of the powder charge and seating depth should improve on that.
One of their first specialty powders was N570, the slowest burning of the 500-seres (double-based) line, which appeared maybe a decade ago. It was originally intended primarily for the .338 Lapua Magnum, and worked very well. But another recent powder is N565, just a little faster burning than N570, which they say works best with 250-grain bullets in the .338 Lapua, while N570 works best with 300s.I haven't tried N565 with 250s in the .338 Lapua, because I haven't had one in quite a while, but I'll take their word for it, since N570 worked great in a couple of rifles with 300- grain bullets.
Of course, that doesn't mean such specific purpose powders won't work well in other cartridges with similar bore/powder capacity ratios and bullets of the same approximate sectional density. They probably would, but VV is willing to tweak powders for specific purposes, no doubt because their powders are so popular among target shooters, who tend to burn far more powder than hunters.
