There are so many variables involved that comparison between guns and loads can only be a generalization. Things such as differences in temperature and humidity, the amount of lube on the patch, barrel temperature, the degree of compression when seating the ball, etc. all play a part in velocity results. Sometimes I think the results you get when wearing jeans at the bench are different than what you get when wearing shorts. And velocity results obtained within three days of a full moon are worthless.