3-shot Shuttle Mag. for Marauder .357 cal

[rsterne]

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....



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....

Bob

[ray1377]

Bob

I really like your design. I've been working on trying to make something like this for my PROD. I like to shoot it single shot but with my old sausage fingers its a bit fiddly at best. Your design will help me at least think of a route I might take. The elliptical o-ring slots is genius

Thanks
Ray

[rsterne]

It should be easy enough to reduce the thickness of the holder and shuttle to fit a PRod, and the size of the holes for the slugs.... You can make the shuttle carry more shots in a smaller caliber, but you will need extra holes in the shuttle for detents....

Bob

[ray1377]

I really like how you designed it without a rear part to the breech piece. Most other mags won't hold a very long pellet because they have a back to them. You design give extra length front to back.  Yours is a 3 shot design with a detent. I'm seriously thinking about making it super simple by just having 2 shots. Just flip it all the way to the left or right and load the side that's empty and then repeat after each shot. Maybe that way I won't need a detent to find center.
Thanks
Ray

[rsterne]

Certainly do-able.... If you load the center shot first, then you don't need the detent when shooting, just push all the way to either end.... If you want a round chambered but the gun safe, load the center slug, then pull back the bolt, don't move the shuttle, and lower the bolt slowly while pulling the trigger so the hammer is not cocked.... Cycle the bolt when ready to fire the first shot....

Bob