After looking on the glock post I saw a doctor optic mounted to a glock. Well I have been wanting to know about this sight and it's performance.  What's the shortest barrel length you can put it on?
I am about to take on a project gun and put one on it. I haven't seen many post on it and I wonder how well it would work on a home protection hand piece. Talk to me somebody.

heres one on one of my 1911's milled in

I have a Docter mounted on my Sig/Hamerlii Trailside .22 (...had a Bushell Holosight on it before that).  

The Docter works great and looks great, but I find that I have to seach for the dot when first raising the gun to the target from the bench or low-ready position.  (I would think that IPSC/IDPA shooters using a Docter sight might have issues with this - - any comments from anyone using it in competition?)  

The Holosight to too huge and top-heavy for a pistol, but the Holosight dot is right there as the gun is raised.  BTW, my Docter has the 3.5 MOA dot, vice the 7.0 MOA one - - don't know if the bigger dot would be that much easier to initially pick up.

This one minor drawback notwithstanding, I like the Docter sight and don't regret getting/using it.