Boomdozer Sillyshell Cylinder

If YOU have a Boomdozer sitting around taking up space, you're too poor to afford a Shellfish or a Breacher, or you just want a powerful modular shell blaster, then this design is for you. My cylinder (more of a spindle really…) holds 6 Sillyshells that supports most common ammo types. Unfortunately, standard Mega XL shells are about 2mm to tall to fit in the blaster, so I've included a shorter Mega XL shell, as well as a bottlenoze shell that both fit within the blaster. 
 

BOM:

1x 40-50mm M3 Socket Head Screw

1x M3 Threaded Insert

A bunch of filament (ideally PETG but I used PLA, so plenty of stuff probably works)

Optional Hardware to Attach Ejector Paddles:

6x 3/32 dia. x ½ inch Brass Rod 

The cylinder should be printing with the hex side up in order to allow it to print without supports, most of the other parts should be fairly easy and intuitive, with holes printed vertically for optimal strength. I recommend that you print most of the parts, especially the spindle with at LEAST a 5mm brim to prevent lifting. The parts should be printed in PETG if possible, but mine was in PLA and they work quite well.

I made this design for the materials that I had on hand, but all of the parts with weird hardware needed are optional so I would recommend starting by printing the cylinder, or cutting off a piece of it in your slicer and testing to make sure a shell fits. The piece to mount the shell on to the rotation mechanism is deliberately oversized, so If it doesn't fit snugly a couple of wraps of tape should help. Any I made this design for the materials that I had on hand, but all of the parts with weird hardware needed are optional so I would recommend starting by printing the cylinder, or cutting off a piece of it in your slicer and testing to make sure a shell fits. The piece to mount the shell on to the rotation mechanism is deliberately oversized, so If it doesn't fit snugly a couple of wraps of tape should help. The part that interfaces with the blaster at the top of the cylinder is separated to avoid layer adhesion damage problems and allow it to print inverted, so you'll need an M3 threaded insert and screw to attach the two pieces together. Any M3 Threaded insert should hopefully fit, this screw isn't particularly load bearing unless you intend to hit your blaster against a tree to get the shells to pop out, so I left some wiggle room for screw size. 

Assembling the ejector paddles isn't necessary, but it provides an easier way to eject most shells (and it's more satisfying). You'll need the brass rods cut to length, I used a janky jig and a hacksaw but hopefully you'll have better tools than I do because it wasn't super fun. The method I used to mount the paddles was to prop the cylinder up on a 2x4, place the lever into it's cavity with the long side facing into the cylinder, drop the rod into the hole and use my remaining brass rod to hammer the pin until it was mounted to both sides and wasn't protruding into the crossing paths. This operation is not for the faint of heart or the soft of fingers, and I might make a better assembly later, but there's not really enough space to mount the levers alternatively so this is my current solution.

I'm looking at making some improvements, such as possibly an auto-ejector mechanism, but I don't have much time to work on this right now so I thought I would get it out into the world. If you have any troubles with tolerances or other parts not fitting, put them in the comments and hopefully I can help. Good luck and have fun!