WEIGH THE BRASS! I shoot a .17 Hornet with a powder capacity of about 12 grains. In the Hornet caliber Remington brass weighs about 5 grains more than Winchester brass. That reduces the capacity of the Remington cases by about 0.33 grains of powder compared to the Winchester brass. In a .17 Hornet that would raise pressures about as much as increasing the powder charge by 0.33 grains. That would be by about 130 feet per second, and the corresponding increase in pressure would be a lot! So, with Remington cases I reduce the powder charge by 0.3 grains. On the other hand, I also shoot a .338-.378 Weatherby with a powder capacity of over 110 grains. I am using some Weatherby brand .338-.378 cases and also some Norma brand .378 cases which I necked down to .338. There is some difference in weight, although I think the Weatherby brand cases are also manufactured by Norma. I think the difference was around 2 grains, reducing powder capacity of one brand case compared to the other by a little over 0.1 grain. A difference in 0.1 grain of powder in a case as large as the .338-378 Weatherby makes little difference in velocity or pressure. Anyway, for it I keep the same powder charge for both brands of brass. Also, this probably will not apply to your rifle, but a friend of mine has a .22-250 with a very tight neck chamber. With one brand of brass the tight neck would pinch the neck area of the cartridges and pressure seemed to go up and crater the primers. Another brand of brass had thinner necks, and otherwise identical loads gave no excess pressure signs. - DON