How do your local laws regard slingshot rifles?

Was thinking of designing something like this, would it be an NFA

Nick Mowrer and James Hall hit center in rifle and pistol

Falcon-GT Slingshot Rifle (300 FPS) – HAMMER SURVIVAL

Ruger MAX-9 Semi-Auto Pistol

Open carry in the United States - Wikipedia

Is selling wrist-braced slingshots legal across the U.S

Shooting a Hank slingshot: Part One, Blog

Survival Item - Pellet Guns

Air Gun Laws

International, State, County & Municipal Laws & Ordinances on Air

The No-Nonsense, Non-NFA 14-inch Scatterguns

The RS-X5 High Precision Outdoor Target Shooting Crossbow Slingshot is the perfect companion for fishing. It features a telescope laser light to help

RS-X5 High Precision Outdoor Target Shooting Crossbow Slingshot With Telescope Laser Light For Fishing