So make sure you are using the red dot with both eyes open, some folks forget that.
With the dot and the regular sight still in place you will find your brain prints the dot on the target and ignores the sight. The flip down sights and gas blocks are an option if the look bugs you but what ever you do, don't saw off the irons. And don't laugh because players here have done that (OK laugh a bit).
So first zero the irons because you can be sure that at some point the battery in that sight will die and leave you high and dry. Then zero the optic.
The term for this is co-witnessing the sights, and it is the pro way to setup.
Airsoft, where nothing is hurt but feelings.