Summary

Here is my slingshot gun project. It's about 95% done. I still have to design a trigger mechanism to actually fire the thing. Also, I still have not thought up a good method for holding the projectile.

Instructions

CATABOLT NOTES:

Work in progress. It still needs to have the "wishbone" actuator that goes around the bottom mount bolt and up to the "launch bridge". The intended bolt diameter is 3/8-16, which can be purchased
in 3 and 6 foot lengths at most hardware and home supply stores. For those not using a comically outdated measurement system, please use anything close in metric. BOM is below:
-The length of the rods can be adjusted to make the gun smaller if need be.

qty. 2 threaded rods 3/8-16 dia. 17.6 inches long.
qty. 1 threaded rod 3/8-16 dia. 30.00 inches long.
qty 17 3/8-16 nuts. Washers optional, but would make for a cleaner build.
qty 2 1/4-20 bolts-1.5 inches long.
qty 2 1/4 20 nuts.

Surgical tubing of the desired length. I have not designed a basket to hold projectiles. This could be handled by the typical leather tab that you see on traditional wrist rockets and slingshots.
Such items can, most likely be purchased commercially at sporting goods stores.