Re: MK2 red dot question
Tube or reflex?
I use a Bushnell Trophy red dot (tube) on top of my Browning Buckmark for the local smallbore Bullseye Pistol league. The cats' meow in red dots for bullseye shooting is the Ultradot, but I shoot pretty decently with my Bushnell Trophy.
If you are shooting something that requires speed such as in a speed steel competition though, then the tube type might not be ideal, and you'll want to look at a reflex style sight.