New to relaoding and beginning to work up my first series of .308 loads with IMR 4064 and 165 gr SGK (SBT). Can someone help me upderstand why the Sierra manual lists the max 4064 load at 43.5 gr and the Speer manual lists 45.0 for a 165 gr SBT? The minimum loads are also different at 41.0 gr for Speer and 37.6 gr for Sierra. I just trying to get and idea of the range I should be working in to optimize the load for my rifle. Thanks in advance.