A little bit late but here’s the pipe pistol references. Again the measurements are very rudimentary as the pistol is largely scrap.

Quick parts list:

2X big side bolts, 1X thin reload bolt 1X medium trigger bolt, 1x length of bracing/strapping metal for grip (I got a 1m length which is more than I needed, Another note is I would recommend a slightly thicker strap than what I used because the grip on mine bends a bit if it’s handled roughly), small bits of sheet metal roughly 1-2mm thick (not aluminum as it’s a lot harder to weather because most paints markings just wipe off, similarly with stainless), gardening wire, 1X big bolt, 2Xnuts to fit big bolt for bolting grip to body, ~21mm OD pipe, slightly smaller spring for cocking mechanism, For the cocking mechanism i actually used a bit of wood and sanding it to the size of the ID in the barrel and glued a small bit of the tube on to it for the metallic look. It would like be easier to just find a bit of pipe that’s very slightly smaller than the ID of the barrel, There is another bolt inside the barrel which sits inside the spring. this is largely to keep the spring straight so just use one that’s smaller than your spring.