Quote:
a pair of screws on opposite sides of the rear base


That is a windage adjustable, a.k.a. standard, base/ring set. Prior to sight in one should center the crosshairs in the scope and then adjust the windage with the scope base to get close to center before adjusting the turret on the scope. This is one situation where a picture would have been worth a thousand words.

Rod, too.

Short cuts often lead to long recoveries.