Its totally clear, from real data, through 10+ barrels, that XBR produces more velocity at max SAAMI, than does Varget. This is without question. Varget is a "below average" choice for heavy bullets going for 2750 FPS in 20" barrel, to match NATO pressures. I should not have said poor, its not poor. Its just not nearly as good as other powders, such as N140. There is no question about this.
According to the reloading data, XBR is about ~60 FPS faster, at the SAME pressure, than Varget.
Hodgdon agrees with me because their load data supports what I am saying as does real world testing
XBR is a superior powder to Varget for velocity. Accuracy, its debatable between the two, both are nuts accurate.
I have tested StaBALL Match many, many times, and there is no way, no chance, in a AR15, that its even on the same planet in accuracy to N140, or a dozen other powers. No way. As far as ball powders, I think its good overall, but AA2520 beats it like a drum, and I would take some other ball over it as well. StaBALL match is way overpriced. Who the hell is going to pay $330 + shipping for 8 lbs when you can buy 8 lbs of N140 for $60 less? that is crazy. Not good value, can't produce the same velocity as N140, and nowhere near as accurate. And its super pricey. Its no chance.