Back in late 2011, I had posted about the .50 Caliber Mark V 50 Repeating Pistol (.50 Caliber Paintball Revolver) used as rental guns at Joe Survival Field in Canada, in the early 80s. Mark V .50 Caliber Repeating Pistol
I have been searching since then trying to find one, and lo and behold, I found 2 in the same week!
Member wild_windy contacted me about rebuilding a pistol he thought might be a Crosman 3357. He sent me pictures and I recognized it as a Mark V 50 Repeating Pistol, long barreled version. I ended up trading him a rebuilt 3357 package for it.
Within the same week a member of TechPB contacted me, wanting to know what this airgun pistol was that he had purchased at a yard sale. Pictures he sent me show it to also be a Mark V 50 Repeating Pistol, shorter barreled version. I ended up purchasing the gun from him for a good price.
Through searching and having one pistol in my possession (still waiting for wild_windy to send), I find them to be modified versions of the Crosman Model 38 .22 Caliber Pellet Revolver (wild_windys formerly being a 38T - [target] with the longer barrel, and TechPBs being a 38C - [combat] with the shorter barrel). The .22 caliber version of the Model 38 was converted, instead of the .177 caliber version, as the .22 caliber version has a larger valve.
Here is a picture of a Crosman 38T, and pictures of the Mark V50s (the one from wild_windy is in rough shape). You can see where they majorly cut out the ball ramp where you pulled back a small slide to insert a pellet (even cutting deep into the valve body itself). They also cut out a large portion of the frame, to insert the custom made large paintball cylinder, and set up a cylinder detent system, screwed into the body from the bottom. They also removed the barrel insert and drilled out the barrel housing to .50 caliber size. The cylinders do not detach, so you have to turn the cylinder and insert the paintballs one at a time (same way you had to do when they were pellet guns). These guns are really heavy and have a very heavy trigger pull (the 38T was so much like a real 38 and so realistic, the Air Force used them for combat training in the late 70s).
I've already ordered 2 valve rebuild kits and will completely rebuild/restore both pistols.