I have a lee modern reloading manual and all it lists is the minimum cartridge length at 2.260 what would th maximum length that it could be? i have my seating dies set so that the OAL is 2.265. Why does the manual not list the maximum OAL? Thanks.

If its to long your bolt will likly not close or be hard to close.

IIRC 2.260" should be MAX OAL for any M16/AR15 rifle due to magazine size. Bolt action rifles can be much longer than that

YMMV

Unless you are restricted by the magazine length, you set the col for your rifle so the bullet is not touching the lands. You find that by using one of those measuring thingies or by trail and error with a magic marker.