A discussion with another forum poster raised some questions about this issue. Is doing this a good idea for a rebarrel job? What are the advantages, disadvantages, etc.,? I am planning on assembling a blank round for the 257 WM I am having built. I was going to take an unfired case run it through my FL die and then seat a 120 grain Nosler partition. HMmmmmmmm to what depth should I seat it? I don't want to seat it too short and then leave myself out of luck if I ever want to shoot another bullet that may be longer. Also I don't want to seat it out to long? Any suggestions? My Speer manual lists the COL at 3.170"

There is no science in this, but I would prefer the bullet base to be even with the base of the neck. That gives maximum grip on the bullet with no crimp, no bullet stuck down inside the case. 120 gr. is the longest .257 bullet anyway. I doubt you will need more. If you cut the throat .050" over that length, it should work very well.

Sniper,

I would seat the longest/fattest ogive (RN) bullet I might ever want to shoot out to the absolute max magazine length.

I would also make sure I had enough twist for that heaviest/longest bullet. Remember that the monometal bullets (Barnes, GSCustom) are long for their weight and might require more twist.

Don