Does moving the scope mount on a rifle forward or backward move the point of impact higher or lower?

Dave@vabch

You are moving one of the references of intersecting lines in space.

...changes the POI.
Rob

Anything you do to any gun (of any kind) will change the POA/POI. Theoretically by just touching the sighting device with a feather would off your sights, even if just slightly.

Moving the scope forwards should move your close zero (before pellet drops usually like 10-15 yards for a 50 yard zero) further, thus making the pellet hit lower at close range.

Moving the scope forward will move your long zero closer (shooting high at the same distance).

Please correct me if I'm wrong.

Either way your POI and POA will be off.