I splerrshed for a labradar chrono and I have some questions. I notice on some powders the longer I go the velocity increases. For example titegroup, book value is 1.100 3.2 grains of titegroup gives 902 fps, I move it out to 1.130 and I increase velocity to 917 fps decrease extreme spread by 22 fps and decrease standard deviation by 8 fps. And I also noticed that with vv N320, 1.142 is perfect... either side of this, shorter or longer, velocity decreases. How do I, or can I, fine tune the OAL to my barrel for best results and accuracy? Or am I just driving myself crazy? BTW I am using a stock Glock 34 barrel.