I happen to own a 22/45 with a 6 7/8 barrel. They do exist and you can also find it listed on Ruger's website. My only complaint is that you can't get aftermarket grips for it like the Mark II. Maybe ruger could work on that in the future. Otherwise, a splendid gun to shoot. Well worth the $250.00 I paid from the shop. Iron sights are best on this thing, as I think a red-dot makes it a little top-heavy.