I can tell you how I do it, and it works every time:

I take it to an accuracy gunsmith.

Seriously, I adjust my own triggers, sometimes bed my own stocks, but that kind of stuff goes to the 'smith.

I only lap the lugs if I am putting a barrel on later, and can control the headspace.

Lapping the lugs with the barrel already on the rifle will increase headspace.

Clark,



Your process seems to be pretty much "normal" operating for most the "accuracy" jobs I know of, and it is how I have done it in the past.



irv & anybody else for that matter,



In a static state you can get both lugs to possess "equivalent" contact area, or very close to it. The relative stiffnesses of each lug and the receiver at the lug reaction point (points of contact) will determine how much of the thrust force of firing is ACTUALLY carried by each lug. It is practically a given that during the force WILL not be equally split between the lugs due to significant relative stiffness differences between the two lugs themselves and the receiver raceway.



What does that mean?



That while you may be "square" in the static condition (unfired), but the INSTANT you fire the weapon it AIN'T SQUARE NO MORE, as it deflects based upon it's distribution of relative stiffnesses!



I feel (actually know) that there are better places to place your attention to ultra precision and accuracy than "squaring" up lugs.



But what do I know I am just a stupid ol' "ASS_CLOWN" for cryin' out loud.



ASS_CLOWN