Ruger Mark 2 vs Mark 3 what's the difference?

The most obvious differences in the Mark ii and Mark iii .22 pistols. I am sure I left out a few things (like the trigger guards being shaped differently and the Mark 3 has a keylock safety feature) but this was just a short quick overview of the 2 models side by side. These are the 22/45 models with 5.5 inch barrels.
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