Has anyone ever used an extra seater plug to accurately measure cartridge length due to the slight inconsistencies of some bullets? For example, I have been loading Sierra Gameking 165gr BTHP in my '06 for years and setting my OAL to 3.35" but the caliper measured length varies say 3.30" - 3.35" in the same sitting. I understand that it's really not important as long as at the olgive it is consitent to the lands right? I just purchased another box of bullets and set up my seating depth using an existing load measured at 3.35", then when loading the new bullets they actually measured 3.34" OAL. Again, I understand it may not be important as long as the olgive measurement is correct. I know there are tools for measuring the length to the olgive and it got me thinking of another way to do it easily and inexpensively. Couldn't I buy an extra seater plug, cut the threads off, "grind" it smooth then use it with calipers to measure the length? I somewhat tested it by taking my seater plug out of the die and measuring a buch of handloads from the case head to a flat spot on the seater plug and they all measured exact. When measuring OAL, they varied. Isn't this basically the same thing as using a comparitor?