How to Zero a Red Dot on a Pistol - also - How to Shoot a Bench Rested Group
So red dots mounted on pistols are very popular now - for good reason! Red dots are both faster and more accurate than iron sighted guns at most distances. It can be daunting attempting to zero a gun - and take a lot of ammo. We'll discuss in this post how to go about it the most ammo efficient way I know how.
If you're more of a visual learner - consider checking out my video on this very topic.
First things first - make sure your red dot is locked down appropriately - there's a good chance you need to be using Loctite and a Torque wrench to install it properly. Let the Loctite cure for at least 24 hours before shooting it.
With that taken care of you're ready to begin. If you aren't a very proficient shooter - and the way I mean to use that term is if you cannot shoot a 1" group at 10 yards on demand - that's probably not you. Then you aught to consider using a pistol rest and shooting the gun rested.
To use the rest - set up at a distance you desire to shoot your dot at - between 10 to 25 yards is probably fine. Make sure you have a target that is very easy for you to aim at. With a red dot it's much easier but with iron sights a black circle usually isn't ideal. Adjust the intensity of your dot down so it's just barely visible.
Adjust the rest to get your gun largely aimed at the target then use your hands to fine tune the aim point. Support your elbows on the surface supporting the rest. You do not need to muscle the gun. When you are satisfied with how the gun is aimed begin to pull the trigger very slowly by conceptualizing it of just moving it to the rear - keep adding pressure until the break of the shot surprises you. Ignore where the bullet hole went - try to aim exactly the same spot and do it again. Do this for at least 3 good shots. Examine your target and eyeball the distance the group is from where you were aiming. Each click of adjustment is going to be 1" at 100 yards - if you're at 25 yards that's going to be 1/4" adjustments, if you're at 10 yards that's going to be 1/10 of an inch adjustments. You adjust from the point of impact toward where you were aiming. For an example - if you are 1" low and 1.5" left at ten yards - then adjust 10 clicks of "up" and 15 clicks of "right". With the adjustment in place - repeat the process - go back to the rest and repeat. Make another adjustment - you should be much closer.
This may take 2-3 iterations to dial it in. It's a good idea, at this point to now verify your zero shooting unsupported and off hand at various distances. I like to use a plate rack. I'll try a plate rack at 10 yards and then I'll try it at 25 yards - if I can connect on plates like I know I aught to I call it good. You can expect to spend 20-50 rounds zeroing and validating your zero.