I made rubber band guns for two young grandsons. This is a version that requires no welding and only a few basic tools. Further, it is more realistic than using a wooden clothes pin for the trigger mechanism.

Supplies

Materials

Scrap wood 3/4 x 1 x 13 inches and 3/4 x 1 1/2 x 4 inches
2 1/2 inch corner plate
#8 wood screw 3/4 inch long
Drywall screw 2 inches long

Tools

Saw (A table saw or a radial arm saw is preferred, but a handsaw would work.)
Drill and bits
Vise
Spokeshave
Rasps and a file

Step 1: Cut Wood Pieces

Use any size stock you like, but 3/4 inch stock works well. The wood does not need to be especially high in quality. Make one piece 1 inch wide and 13 or so inches long. Make another piece 1 1/2 inches wide and 4 inches long for the handle. Cut the ends of the second piece at an angle of 20 degrees.

Step 2: Shape the Handle

I used a spokeshave to shape the handle and smoothed it with a rasp.

Step 3: Attach the Handle

I attached the handle with a long drywall screw. I could have added some wood glue between the handle and the frame of the gun. I drilled the hole through the frame of the gun large enough that the screw threads do not grab. Drill the hole in the handle a little smaller so the threads do grab and firmly hold the two parts together.

Step 4: Notch the Frame for the Rubber Band

I used a smaller diameter round wood rasp to make a groove across the front of the gun frame. The rubber band rests in this groove before the gun is fired.

Step 5: Trigger Mechanism

I used a 2 1/2 inch corner brace for the trigger mechanism. I placed it into a vise so I could bend one leg over. See the second photo. The third photo shows bending the corner brace just a little to make the corner a little greater than 90 degrees.

Step 6: Attach the Trigger Mechanism

The first photo shows locating the pivot hole for the trigger mechanism. Hold the leg of the corner brace on top of the gun frame firmly against the top of the frame. Make the trigger’s location comfortable with relation to the handle. Remember that it is for a chld and size things accordingly. Make certain holes in the corner brace on the top of the gun frame are not over the drywall screw. Drill for the wood screw used as a trigger pivot and turn the screw home, but leave it just a little loose for a smooth action.

Step 7: Install the Rear Pin

The rear pin holds the rubber band until the trigger mechanism pushes the rubber band upward to move over the pin and fire the rubber band. Drill a deep hole inside one of the holes in the corner plate. Make it 3/16 inch in diameter. Push a 3/16 inch steel rod into the hole. A wooden dowel could also be used. The photo shows where the firing mechanism collides with the rear pin. Cut the 3/16 inch rod used for the rear pin just below the contact point. File the rear pin so the release action is smooth and unhindered.

Note: The trigger pull on this gun is quite firm. To make it softer for a smaller child, drill a new hole in the corner brace nearer to the pivot point and locate the rear pin there.

Step 8: Loading and Using

This rubber band gun was designed to use #33 rubber bands. That is an intermediate size. A stretch of about 12 inches works very well with those bands. They will travel about 20 feet or more when the gun is fired.This gun is quite accurate with respect to high or low. But, it first shot a little to the left because the rear pin of necessity is set off to the right. I trimmed the front left part of the frame to make the rear pin more centered with the front of the gun. It is now accurate and shoots neither left nor right.

I find it best to place the rubber band over the rear pin first. Place a thumb or finger over it to hold it in place. Pull the rubber band to stretch it and pull it over the front of the gun so the rubber band rests in the groove.