Actually, The MK I came out first. First caliber was .357mag. Flat safety levers, non-adjustable trigger assembly, smaller slide stop. Then came the .41mag and .44mag. Slide assemblies for .41 and .44 were identical (i.e., interchangable). Early on, I think there were seperate slides for the .41 and .44, the only difference was the engraved markings on the side indicating caliber. Later on, they were consolidated to the '.41/.44' marking.
Next came the MK VII. Extended safety and slide stop, adjustable trigger. An adjustable trigger assembly was introduced for MK I models. Early MK VIIs had the choice of 6", 8", 10", and 14" bbls (Gotta 14" on mine.), adjustable sights introduced (needed to be installed by buyer), Hogue and wood grips available, nylon holsters available. .50AE introduced late in MK VII life. Slightly different frame for .50 than other MK VIIs. I think all MK VIIs (as are MK Is) are Isreali made, some early MK XIXs are also.
MK XIXs are essentially .50AE MK VIIs. Interchangable slide/barrel assemblies for other calibers made for MK XIXs will fit MK XIXs and .50AE MK VIIs. Will NOT fit other MK VIIs and MK Is. All slides for all calibers are identical. .440 Cor-Bon introduced, I think it's a .50AE necked down to .44. A set containing .357mag, .44mag, .50AE can be had between $2400 - $3700 from the factory.
Goto :
http://www.magnumresearch.com/
------------------
- Ron V.