has anyone done the mark vii conversion to the xix? how much did it cost, anyone other than magnum research carry these?
Just pick up a whole new pistol if you are looking to go to a 50AE.
You are talking about a complete new top (the thicker slide that the 50 requires driving the whole works, and the barrels to go with them).
The 50AE pistol in a model 7, is a xix since it it required the thicker slide for the thicker barrel (just not marked that way). The xix series is just the 7 series 50AE top end, with new barrels in below smaller calbs to work with the now standard 50AE thicker slide used on all that series pistols.
To sum it up,
The upgrade to the first series was the new safety levers and the adjustable FCG (what became the 7).
The upgrade from the 7 to xix, was standardizing the 50AE 7 series slide for all calbs, so all the new style barrels would now fit the thicker slide.
On the 1 and 7, if you had a 44, it was just bolt, barrel, mag swap to go smaller. If you had a 50AE (7), you had to change the slide as well to go to the 44 and smaller calbs. Now on the xix with a 50AE slide, all the smaller calb barrels are made to fit that slide.