Lane's Weekly Stupid Question

[Lane]

These discussions have been incredibly helpful and enlightening for me. But, I've always been curious, and enjoy learning as much as I can about any given topic (sometimes obsessively).

Anyway - my question now is around OAL. Obviously, internal pressure can be greatly impacted by seating the bullet too deep. Every load sheet I've seen will list a Minimum OAL, which makes sense. But, why would the OAL ever vary? Specs I've seen show the OAL of a .45ACP cartridge to be 1.275. Should I be cranking out every round right at 1.275, or is there a reason to vary from this?

Inquiring minds (or, in my case mindless) need to know...

Lane