If you seat a bullet deeper than usual will it change the pressure

generated and potentially mess up your REGULATION? What about

if you seat the bullet LESS deep than usual?

Not sure about extremes either way, but I adjust my bullet seating depth to whatever works in my guns. ie after working out a load that regulates, I play around (read "tweak") the seating depth to see if I can get it even better (the regulation that is).

I don't spend hours on it, only a few rounds and if nothing changes, then I just leave it where it is normally.

I haven't noticed any change in pressure from Visual inspections
but as I said at the start, big changes in seating depth may have some effect.

All other aspects being equal, seating depth will cause greater or lesser pressure (read velocity). Regulation could be affected in the process.

quote:

Originally posted by bigfats:
All other aspects being equal, seating depth will cause greater or lesser pressure (read velocity). Regulation could be affected in the process.

+1

Just seat it on the cannelure and crimp and you'll be fine. Consistency is what you are after.

Most of the time, the cannelure seating depth will be fine. Most people do under estimate the importance of seating depth though. Many of these older vintage guns have different throats. My experience has been that my guns seem to like .005" - .020" off the lands.

I have seen some that prefer much more jump though. My friend's Lang 450BPE simply hates the bullet close to the lands... at .060", it shot 1.5" groups at 50yds. When he tried .005" with the same powder charge, the group went to 10". I was shocked.

Bottom line is to shoot it and play with it.... You will figure out what it wants.
ND

Jack....of the 7 doubles I have owned, or own, and a few more I have additionally loaded for, I always started at the groove (cannelure) and went from there. With the bullets that are meant to mimick bullets of days gone by (Woodies), I never had a gun shoot better than at the groove. With other types, NF's, Swifts, etc., I started with an OAL the same as the Woodies and went from there.
Always seemed to work out where they shot as good or better than me and my buddies could.

Gary
DRSS
NRA Lifer
SCI
DSC