I am comparing the loads to a 16 inch barrel, I have 16 inch barrel data from a source. I have compared data from 16 inch barrels and 20 inch barrels, there is plenty of information on this subject online. Depending on the powder used there is about a 100 to 140 fps difference between a 16 and 20 inch barrel, slower powders have a larger velocity difference.
That is a great article on Case head swipe, I put it in my favorites, it appears that I do have a CHS issue with some of the loads that I tried, the issue occurred only with H335 and Vihtavouri N-135 powder, with the N-135 load CHS appeared early, only about 1/2 grain above starting load, with the H 335 load the issue occurred much later. I thank you for that article, it puts my mind a little at ease.
