• Mossberg Owners is in the process of upgrading the software. Please bear with us while we transition to the new look and new upgraded software.

Trouble holding zero


Elite Member
I bought a Glock 40 MOS 10mm with a Vortex Viper MRD to deer hunt with and as a year round woods gun. This is my first and only 10mm, so far. I replaced the OEM sights with Trijicon suppressor night sights. This appears to give me lower 1/3rd co-witness. I am having trouble zeroing the red dot after over 700 rounds. It does not seem to hold zero. I am thinking of removing the sight altogether and installing a set of adjustable sights and calling it good, but I don't want to give up on the red dot. I have a couple questions for the people with more experience with the MRDs.
If the iron sights and the MRD are sighted in for the same range (for now) wouldn't the front sight and red dot be stacked on top of each other or overlapping? Mine are off from left to right, which drives me crazy. (OCD I guess)
I would like to have the irons sighted for say, 15-25 yards, depending on how well I can shoot the pistol, and the red dot zeroed for longer range shots like 25-50, depending on the drop of the bullet. I am using Underwood 200 grain XTP at 1250fps and the Glock will be braced over a rest when deer hunting. Is this a realistic goal, or am I just wasting ammo trying for this?
Lastly, am I just overthinking this whole deal? I realize that they are separate sighting systems but I feel like they should work together.
Thanks for any advice.