Mounting position of holo sight on a pistol

[Magoo]

How do you decide how far forward/back along the rail to mount a holographic sight on a pistol? From looking at pictures, it seems most folks place holo and red dot sights pretty much centered over the action/all the way forward on the rail.

On my Buckmark with a TacSol rail (the optic is a BSA PMRS if it matters), I've got about 2-inches to play with. The farthest back I can place mine (where I have it now) gives me access to the dial to chose between reticles. This puts the lens about 1/2-inch behind the chamber. One reason I could see mounting it far forward on the BM is to have access to the rear takedown screw so you could leave the optic on when breaking the gun down and not have to rezero. But I rarely break this gun down for cleaning.

Is there a "right way" to place these, or is it purely personal preference? Is balance a part of it and it makes more of a difference with (presumably) heavier red dots than it does with holo sights?

 

[mbopp]

I have a Bushnell Holosight (no longer made.) It's a single-screw mount and I filed an extra slot in the mount to put it over the action.

 

[K-Rod]

I have a 22a bull barrel with a Holo. I at first put it closer to center but after shooting it, I moved it back almost to the rear sight. I found the even though the Holo sight doesn't weigh that much, with the bull barrel it makes a difference with it forward. Now that it's back farther, the pistol balances better.

 

[BCRider]

It really doesn't matter a hoot on a .22 where you don't need to worry about ejected casings since they come out low and below the full length top rail. So other concerns become more important such as access to take down screws you mentioned and being able to reach the controls. So put it where it suits you and serves those other purposes.

On bigger center fire stuff such as IPSC Open guns it's a lot more limited due to the need to avoid blocking the ejection port and to try to avoid picking up too much of the fouling from the gases coming out the muzzle mounted compensators and to a lesser but still very significant extent the ejection port. Such fouling dusts up the optics and reduces sight visibility pretty quickly if not controlled and allowed for.