I start at the lands whenever possible, call it lightly touching with no chance of debulleting a load. Far short of engraveing anyway.
Something that may be interesting can be demonstrated with the rod techinique since there is no case involved the bullet is just put in the barrel. Simply dropping the bullet in under its own weight will result in a jam of about 35 thou compared to easing it ahead feeling for the slightest resistance.You can push them in hard with the Stoney point/Hornady tool too. The dented neck method results in considerable jam, so when the old timers suggested using that method then backing off 30 they probably accidently were back at light contact and not jumping anything. Its not like we’re measuring to an anvil or brick wall or something else that has a definitive touch/no touch point.There’s a lot of room for interpetation and one guy’s jumping 20 is the next guy’s 10 jammed.
Either way it’s a starting point to experiment from, and they all work. It’s just their number, not a set in stone absolute. When people talk about varying their jump 3 thou at a time all I hear is they made the cartridge 3 thou shorter. They might not be jumping anything, just playing with lighter jams. Not that there’s anything wrong with that.
