Don't know about the 22/45, but I have shot the Ruger Mark III's.
Extremely accurate pistol -- used it hunting gophers out on the prairies of Montana.
When all you can see of the critter is his head sitting above his hole in the ground, you have a very small target to aim at. Could usually hit the critter and when I did miss, I usually blamed it on operator error and not the pistol.
And oh, BTW, this was using open sights.
Just my opinion though. . . . .