[Brian Pfleuger]

There is some variance in length due to things like plastic tips and whatnot but as long as the basic construction is the same, and not a solid bullet like Barnes TSX versus traditional copper-jacket lead core, the variances in primers, case capacities, chamber dimensions and powder lot burn rates will more than mask any small differences in bullet length.

Starting low and working toward max also stabilizes the results, any change that produces significantly higher pressures should be reasonably evident before you reach a dangerous situation.