it was a few years back and i'm still looking for the data, however we used a chronograph, and mesured vel. We used 50 cases from the same lot all fired once. half were cleaned half were not, they were all loaded with the same bullets, primers and power from the same lots. the loads were all shot in 5 shot groups, the gun was cleaned after each group. The dirty rounds all fired between 5 to 8 flbs higher than the clean ones. it may not be 100% accurate, but I'm saying higher vel. =higher pressure.