I realize I'm something of a new guy, but I need help from someone who has some experience. It says to adjust them using calipers (I have some), but I don't really understand that process and I don't want to jack up a bunch of 223 brass playing "trial and error". I read somewhere that it comes from the factory set at 1.75, but I'm more of a "trust but verify" guy. I'd like to know exactly how its set before I start grinding.

Any thoughts from the experts on how to get my measurement setting so I can get to work?