This is the old Trumpeter kit, which is still available for ~ $85.00 If you can find it. I got this from John Ford's piles. The box was crushed along with the lower hull. I had to pry, cut, glue and clamp several sections to straighten it out again so it was usable.
Then I had to research it to see if I could figure out how the mechanisms were supposed to work. There are lot of missing pulleys, chains and hydraulics as the photos of the actual captured prototype only captured the parts visible. Much of this was not documented where I could find it, so I tried to reverse engineer from what was available. I added enough of it to make it look like it might work.
I painted this in sections making the cannon a complete separate kit, which was detailed enough to stand on its own. I added crew stowage and some support steel, cables, chains for the deployment mechanism. The track was rubber and I had to insert broken drill bits to shape the sag.
I lightly weathered it with oils and provided the scratches, scrapes and rust as applicable.
Vince B. 6-24-17