I needed a slug magazine for my bottle-Rod to hold 3 shots for deer hunting… I converted my .35 cal pellet shooter to a .357 cal slug gun by going from 2200 psi regulated to 3000 psi unregulated, details in this thread… https://www.gatewaytoairguns.org/GTA/index.php/topic,119868.360.html
The first 3 shots are just over 200 FPE, and the 10th shot is 180 FPE, so a great tune for deer… The 3-shot magazine turned out equally well, here are some photos… First the 3D printed parts (made from PETG)…
The shuttle has internal O-rings in the holes to keep the slugs from falling out… I printed the groove elliptical so that the #012 O-ring were flush on the side, and only touched the slugs top and bottom… They stay in place but the O-ring does not interfere with loading or chambering… It will hold most 80-140 gr. cast slugs…
The holder for the shuttle just snaps in place… It sits over the barrel stub (that normally locates the magazine in an MRod), and there is a 1/4" O-ring in the top of it protruding about 0.010" to act as a detent for the shuttle in the center position…No detent is needed in the end two positions, the shuttle has stops to make sure the chambers line up with the bolt… One end stop is removable for assembly/disassembly…
When the mag is centered, both outer chambers are available for loading, simply insert the slug from the rear…
When you push the shuttle to one end, you can load the center chamber…
and the other end is flush with the receiver…
I suggest that once loaded you chamber the center slug and shoot it first… Then you can reload by simply pulling the bolt back and sliding the shuttle to either end, with the positive stops there is no fiddling to find a detent (except for the center position, which is why to use it first)… I plan to do some experimenting with CF Nylon filament, and I will make one of these using that… The files are below… I used 60% Cubic for the shuttle, and 100% infill for the endplate and holder, with 0.2mm layer thickness…
I have added the design to Thingiverse, at the following link…
Bob