243winxb, the deck height of the shell holder from the deck to the top of the shell holder is .125, Redding sells + or _ shell holders, from $40.00 to $60.00, so there is an advantage to measuring shell holders with a height/depth gage, RCBS will exchange shell holders that are not within specification, and will forward all callers to Redding if the caller wants competition/bench rest shell holders. Why? I do not know, a feeler gage will can be used to duplicate all variations of special shell holders from -.012 (.017 under a go-gage) under SAMMI specs for a maximum sized case to my favorite, the .016 over minimum (.011 over a go-gage).
If you have a shell plate that has variations in deck height, let Dillon know, remember, the Dillon ram is hefty and the shell is not sized in the center of the ram, the shell in the shell holder holder is off set (cantilevered), on small cases, not a problem, with good lube on large cases there should not be a problem their either.
The variation in deck height of a shell holder plate is directly related to the amount the shoulder is moved back, again there is no support under the shell plate, the shell plate and ram must be tight and tough, you could purchase a lot of tools but measuring the distance from the head of the case to the shoulder would tell you if your Dillon is producing (ISO) same-o ammo from each station.
RCBS made an add-on progressive press called the Piggy Back l and ll, the maximum length case that could be loaded was the .223 Remington (5.56 NATO), the diameter of the ram and off set of the shell holder positions put the leverage too far out from center to have the leverage required to size larger cases.
F. Guffey