Originally Posted By: Tgunz64You mean the same feeler gauges for checking spark plug gaps? If so what are those for?
Yes.
If you use the gauges to set the scope so the bottom flat section of the turret is parallel to the top of the rail, the vertical "wire"'of the reticle will be perpendicular to the base.
Next step-hang a plumb line at about 50 yards or so (I use a 3/8" braided nylon rope) , align the vertical reticle with the plumb line, and adjust your level until the bubble centers.
Then tighten the little screws and lock the level into position.
The base is square to the receiver,
The reticle is perpendicular to the base,
And the level is set according to the plumb line.
*