RE: Inconsistant bullet length and COL?
I just posted this elsewhere, but it seems to work here too.
You might want to consider buying a Sinclair Bullet Comparator ($16.25). The Bullet Comp. gives you a way of measuring the cartridge length based on bullet minor dia. using your caliper. That is needed when you start working with bullet seating depth or jump of the bullet to the rifling. Measurement to the bullet tip is rather useless except to be sure your finished round will clear any magazine out there. I have the best accuracy with my .22-250 with about .020" of jump. It does make a difference. Good luck.