"Full length sizing without shoulder setback"
Davery25, I am the only reloader that understands the question. There is no such thing as full length sizing without touching the shoulder with the die. You will hear 'it' over and over and over etc., you just gotta full length size the case like bench resters and long range shooters and self appointed experts.
I size cases from short chamber to cases that are longer than a field reject chamber, again, that could be 26 different length cases from the shoulder of the case to the head of the case, all with a press, die and shell holder and the companion to the press tool, the feeler gage. All 26 different length are under the heading of a specific caliber like the 30/06 or any caliber that has a full length sizer die that will screw into a press, and a shell holder. The RCBS shell holder works, the Lee works better, I can size a case that is .012" shorter than a minimum length (minimum length-a foreign term to a reloader), I can size (shorten) a case an additional .002" with the Lee die because it has more slack than the RCBS shell holder.
I size cases to the chamber, to accomplish that I must know the length of the chamber from the shoulder/datum to the bolt face. Long before I had a barrel with a 35 whelen chamber, long before I had a 338/06 barrel with a 338/06 chamber I had dies for both, WHY? Without SAAMI, with out a reloading manual I can determined the length of the chamber from the shoulder of the chamber to the bolt face by first necking the case up to 35 Whelen or 338 then start sizing the case neck down until the chase chambered. It was easier to start with 280 Remington cases, all that was required to do was adjust the full length sizer die off the shell holder with out making some wild guesstimate of a fractional turn if the die.
Back to the feeler gage, it is a standard, it is a transfer, and! it is a verifying tool, as when adjusting the die off the shell holder by what ever means like wild guesstimates, after making the guesstimate adjustment verify the gap with a standard, like the feeler gage.
Sizing: for the non mechanically inclined reloader it is impossible to express in 10 words or less the ideal the ram travels the fastest when going up and or down and slows down when it reaches the top and or bottom. Leverage: When sizing the press has the greatest amount of force when the ram reaches the top of its travel. Most difficult concept to understand is when the ram reaches the top of the stroke, needless effort is wasted when attempting to size the bottom of the case, I avoid the wasted effort by knowing the length of the chamber, again, I size to the chamber.