If you adjust the laser to the same aim point as the iron sights, then sighting with the laser should result in shots with the same placement and accuracy as the iron sights.

Two possibilities:

The unlikely one is that the laser is loose in the frame. You should be able to determine this simply by sighting down the iron sights. If the laser moves from shot to shot, maybe it is loose (or maybe your iron sight picture isn't as stable/repeatable as you'd like).

The more likely possibility is when you are shooting with the laser your focus on the red dot is interfering with a smooth, consistent, trigger pull. If that's the issue, then turning on the laser but shooting with the iron sights but allowing the laser to have an increasingly greater "feel" in the aiming - might help develop better technique with the laser.

M.