just start at the lower end of the load table for those heavy bullets and watch for flattened primers or hard bolt lift if you don't measure case head expansion......I don't have a fast twist bolt gun now and load for a 1-9 and 1-12.......but my old loads used Win 760 in the 27.5gr. for a 75grain load loaded for single loading with the bullet seated just off the lands.....H4895 at 24.0 with a Sierra 80 grain bullet .....as for OAL....just don't seat the bullet deeper in the case in a load you worked up with the bullet seated out futher.......as this almost always makes pressure rise.......and the style of bullet....A VLD vs. standard boattail can change pressure so drop back if you use a different style,to a starting load.....my notes also show AR2208 at the 25.0 gr. level with the 80 gr sierra ........these loads were all with Rem comm. brass and Rem. 7 1/2primers....hth..good luck and good shooting-loading!!