More than it would cost to do a ground up, bare receiver build...
What do you consider ridiculous? There is a lot of work that goes into a 51K.I want a 51k but the prices are rather rediculous, how much do you think it would cost to do a conversion of a V-51 or even a 91 clone.
That's because everything is custom - the barrel, cocking tube, carrier, recoil rod, receiver cutout over the trunnion, cocking slot, end cap, front grip push pin hanger - about the only parts that can be used as purchased are the cocking tube support and handle, the trigger group, the trunnion, and the bolt head. You'll also need a different locking piece, but it at least can be purchased.I want a 51k but the prices are rather rediculous, how much do you think it would cost to do a conversion of a V-51 or even a 91 clone.
I machine the inside of the cocking tube support and the outside of the carrier so that when it's cocked the cocking tube support does not try to come out the ejection port.That's because everything is custom - the barrel, cocking tube, carrier, recoil rod, receiver cutout over the trunnion, cocking slot, end cap, front grip push pin hanger - about the only parts that can be used as purchased are the cocking tube support and handle, the trigger group, the trunnion, and the bolt head. You'll also need a different locking piece, but it at least can be purchased.
You would save no work at all by starting with a 51, and like shattered says, would cost more because you'd first have to carefully demil the 51.
I do something similar, but with an unmodified cocking tube support. Or used to. I don't have time for custom builds like that any more.I machine the inside of the cocking tube support and the outside of the carrier so that when it's cocked the cocking tube support does not try to come out the ejection port.