I tried to make the memory gun from gravity falls. The issue I ran into is every shot of this darn thing is slightly different so the ability to figure out any dimensions is sorta moot. This is most of the parts that should be 3d printed however their are parts that aren't really suited to 3d printing. Which can be bought at a hardware store or for some a specialty shop. There is a plate that slots into the back of the gun in case you don't want to put electronics inside.

You will need: -A flame tip lightbulb -A lightbulb socket with an outer diameter of 38mm to fit in the barrel part. -A red piece of clear plastic for the shield shown in the cartoon that goes at the end of the barrel, the shield is the template for this -2 brass hinges for the tube and it's door -1/8" rod for some of the pivots -.05" rod for the trigger that will connect the spring to the body -a small spring