Bob,

Side, rear, & objective parallax adjustments work equally well in correcting parallax.

The problem, is that when you adjust the parallax, inevitably, the point of impact will also change

This shift occurs in both fixed & variable mag. 'scopes.

In the very best of scopes, this shift has been virtually eliminated.

There has been some debate about which type of adjustment (side, rear, or objective) causes the least shift - the answer is none of them - it all depends on the quality of manufacture.

Have fun & a good Easter

Best regards

Russ