Thread: Using comparator tool when seating projectiles.

Originally Posted by gqhoon

It’s quite common for rifles to have a CBTO tune window (node) of 0.006” (1.5mm). So using your example above, the 1mm variance either way equates to 0.008” between shortest and longest CBTO for a given projectile. So while you consider it to be tiny, it’s is enough to put you well out of a previously good performing node.

You really need to understand that the slightest difference in shape or profile of the ogive, will give a massive difference in CBTO measurement.

if the projectiles are not the same at that given point on curve of tip...they wont be the same at fattest point either..so point is moot.. either they are the same projectiles with same shaped jacket or they are not..agree the cartridge overall length will vary because of tip shape..but he point the seater pushes..for want of better word,should be the same for all your projectiles in that batch,it will be same fatness,so no different than seating from your olgive point.... the fattest part closest to the tip.