Setting Mechanical Zero

[ar15barrels]

It happens more frequently than we'd like that the holes in the receiver are drilled improperly and not aligned with the bore. This really needs to be corrected by drilling out the holes for 8-40 screws and centering them up rather than windage adjustable hardware. This is also assuming that your base and/or rings are not the culprit.

Starting with the windage perfectly centered will all you to see IF you have such a problem.
Simply bolting it all together and adjusting for POI wil not tell you much.

[maxicon]

As far as windage adjustable bases and/or rings being bad for the scope, yes, that is possible due to binding. There are ways to minimize (and even eliminate binding) in this type of setup using a lapping bar.

Aside from the risk of torquing the tube, I dislike windage-adjustable rings because they can lose zero badly when you remove them and re-install them, due to having adjustments on both sides. With fixed rings and rails that are in spec, you can move scopes around, even from gun to gun, without being too far off.

The one pair I still have are loctited on one side so they don't shift when I remove them. I put an alignment bar in them when I glued the screws down.