Follow Sevens's instruction to let a resized case find the correct depth with the collet nut adjusted lightly. You may even want to run a number of cases in to make sure it is up where the case with the thickest head needs it to be. For most bolt guns, any setup method will work well enough, but if you are loading for a semi-auto with a floating firing pin, like an AR or a Mini-14, then you don't want the end of the decapping rod to push hard against the case web during decapping. Doing so can deform the web brass down into the primer pocket, decreasing the pocket depth slightly. This can cause primers to seat a couple thousandths closer to flush with bottom of the casehead. That increases your risk of slamfires. You want the pockets to remain as deep as they are supposed to be for these guns.
Firing pressure also deforms the web back slightly. It's one reason many folks clean primer pockets with a depth uniforming tool, so it tends to set the bottom of the primer pocket back to full depth at the same time.
So, Sevens's method is best for the mentioned rifle types. You need to be aware different case head designs in different brands. Over a number of years difference in age, there can be production changes in the same brand. Some now outsource their brass manufacturing to foreign companies so the exact die dimensions used can even change lot-to-lot. If you're loading cases that aren't all from the same lot, find the one that pushes the rod up highest, then use that setting for all. You can even add an extra 1/32" to the rod height if you are unsure.
