well...I got the basic idea done.
The exact location and angle of both the dieselpump and catch will be determined during the build.In the schematic, the dieselpump is not even close to being in the right location.It will be at the very start of the stroke.
I want to tuck them in as much as possible.So I might put them lower or higher up on the sides.
the barrel/pistonhousing assembly breaks open and an arm connected to the stock drives the piston to the catch.
The barrel is prevented from breaking open by a bolt type lock that also minimises dead space.
I'll try and figure out if I can " automate" the cocking of the hammer and the dieselpump by synchronising them with the breakbarrel action.
If I feel up to it I might add a mag in this cycle.
The catch is released by a rod, wich gets struck ( indirectly) by the hammer. I'll make the rod float as a safety.
Depending on the force needed to cock it I might leave out the shoulderstock.
Anyway...here's the basic scheme:
( lot of work and lots of welding!!

)