I recently switched to minimags for my 10/22.  When I zeroed it at 50 yards, all was well.  But when I shot it with the same zero at 25 yards, it was printing about 1/2 to 3/4 of an inch to the right, dead on vertically.  I tried again at 50, and still right on.  This doesn't seem to makes sense to me.  Do other rifles do this?  What might cause it?

Very odd. Is this with a scope or irons?

What was the wind like that day?

If you're zeroed POA/POI at 50, your POI should be about an inch low at 25.

Scope.  I would have expected what you predict as well.  There was a little wind, but it was consistant enough that I doubt it was the issue.  I've got no idea what would make this happen.

Okay, here are some possibilities:

1. Scope not centered over bore.

2. Canting (tiliting) the rifle as you shoot. You sighted in compensating for this at 50, and it showed up at 25.

3. Scope parallax. If your scope is set for 50 or beyond, you could easily have enough parallax to throw it off that much at 25. I've seen parallax move the crosshairs as much as 2-3" in any direction at 25 yards!

4. Wind could be a factor. Your 50 yard sight-in compensated for it, but wind effect is negligable at 25.

5. Some combination of any or all of the above factors.

Check your parallax, make sure the gun is straight up and down, and try your test again on a calm day. I bet you get a different result.