Trumark slingshots / catapults ammo valve in sling shot handle
The top picture shows handle's bottom valve: Trumark's FOLDING slingshots are the only slingshots in the world that store ammo in the handle. The patended handles are molded hollow in one piece, and are not glued or riveted together. Since the wrist-brace is secured around the front of the handle, there is room for the flip-valve on the handle's bottom to be opened to the storage chamber inside. See more ammo-chamber patent detail here.
Trumark Model S9 slingshot without wrist-brace.
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