I'm still learning how to tune QuickLoad and have a question about the Burning Rate Factor (Ba). I have two loads, each of a different chambering (7mm-08 and .338-06). I'm using Varget in both of them, the same lot (same bottle). I have input the bullet dimensions, seating, and case capacity for each into QuickLoad. I have chronograph observations for each load (LabRadar), conducted around the same time and atmospheric conditions. In the first load (7mm-08), QuickLoad is underestimating the observed velocity. By increasing the Burning Rate Factor by 7.8%, I can match my observed muzzle velocity (and I'm just over Max Average Pressure). In the second load using the same powder, QuickLoad is overestimating the observed velocity. By decreasing the Burning Rate Factor by 2.3%, I can match my observed muzzle velocity (and pressure is ginger). Question: (1) Is this weird? The impression I have gotten from reading QL user comments is that the Burning Rate Factor might need to be adjusted, as lot-to-lot variation exists, but you would expect that entire lot to be of a comparable rate. Or (2) is this normal, as one cannot compare burn rates between two different cartridges even using the same powder due to other factors? Or (3) is this an indication that I should be looking at other factors to tune in QuickLoad besides (or in addition to) the Burning Rate Factor? FYI, the weighting factor for both cartridges defaults to 0.5 and I left it unchanged.