Choice of star or roll crimp can also make a pressure difference. I've seen reports of 200-500 psi less when star crimp recipes are roll crimped and at least one report of a recipe where there was no difference. As in all hand or reloads, component variance from a published and tested recipe without testing is a no-no. The pressure differences in using different primers in some loads are eye openers and maybe barrel openers.
http://www.armbrust.acf2.org/primersubs.htm