Rubber Band Gun - Interchangeable Barrels

thingiverse

Update 6/5/18: Tightening the fit at the leading edge of all four barrels was a priority, so they were replaced entirely. If prints are already loose, use a hair dryer or heat gun to soften plastic and nudge the bottom edge by a mm or two for a tighter fit. Looking for a rubber band gun led me to design improvements over the original. A few changes came to mind as I examined the predecessor and subsequent prints. Here's the result. I made the barrel removable, adding longer, interchangeable options. Although they allow using longer bands, those exerting excessive force on the action may not work well for long periods. The thickened part of the barrel is on top. Adding a piece to hook rubber bands connected to the trigger was another improvement. Reworking the wheel and trigger aimed to eliminate chain-fires and make it more predictable. It's been partially successful, but stiff rubber bands can still cause simultaneous releases. Printing in polycarbonate would help prolong its lifespan. Thinning side plates and rounding edges of grips and the trigger were additional updates. Screw holes in the top plate allow for attaching hot glue or CA to make it a single piece. Alternatively, sheet metal screws enable easy removal of the side plate. One hole remains incomplete due to a printing error. A shield on both sides of the trigger prevents bands from falling into the mechanism and jamming. I'm grateful to lazydba247 for the idea and model used in the Upgraded Wheel For Rubber Gun design (THING 603697), which I customized further. Make sure the wheel is installed over the axle first, followed by the smaller shield on top. Gluing these pieces together isn't necessary. The original design's barrels, trigger/wheel, trigger rubber band tether, and side plates can be interchanged without affecting critical dimensions. As with any firearm, avoid pointing it at anything you don't intend to shoot! About The Action The trigger mechanism is more suited for a pendulum clock than a firearm or its replica. Instead of releasing the projectile when squeezing the trigger, it acts as a SET or ARM - (TICK), so releasing the trigger fires the rubber band (TOCK). Despite improvements, the mechanism may still release multiple bands with stiff bands or worn action parts.