Starting to see the Mark IV get unavailable, get yours today before they turn back to the last design. JMO.
Rumrunner is correct - the MarkIV was in the works for a couple years prior to the release of the Victory 22, with a few different approaches attempted.
I suspect the Ruger design will revert to a cam-lock front arrangement tried previously, instead of the cheaper-to-produce hinge pin, and keep the rear locking stud, and otherwise resembling the MkIII changes. This makes manufacturing sense once they transfer the Mark IV patents, but who knows? Machining the one-pc frame is established (soon a supplied part) and would be costly to revert to welding and polishing.
If I were king, I'd look into buying Dino Longuiera's patents as they are not yet consumed by S&W, and would make for a fine MK3.5, et al. :lol: