Results Variations in average velocity (and uncertainties) for both the .300 Win Mag and the .25-06 loads with the six different lots of or powder are shown in Figure 1. Lot B had the lowest average velocity of 3122.5 ft/s in the .300 Win Mag and 2832.9 ft/s in the .25-06. Lot D had the smallest velocity variation compared with lot B at 11.9 ft/s in the .25-06 and 13.6 ft/s in the .300 Win Mag. Lot E had the largest increase in velocity compared with lot B with an increase of 111.9 ft/s in the .25-06 and 111.1 ft/s in the .300 Win Mag. Except for lot A, the increases in velocity are surprisingly similar for the a given lot in both cartridges. In fact, the velocity variations with lot number of the two different cartridges have a correlation coefficient of 0.96 (including lot A). This high level of correlation demonstrates that the velocity variations depend much more strongly on the lot number than on other factors such as bore, brass, primer, or bullet. Table 1 shows the actual mean velocity of 10 shots for each combination of load and powder lot.