A lot of people out there are trying to print a weapon that can fire conventional ammunition, its time to think outside the box and create 3D printed ammo that can be fired through almost all 3D printed weapons, This is my first CONCEPT .75 cal round on a shortened 12 G shell with a 9 mm Rimmed blank propellant cartridge firing a 14.5 mm heavy plastic Bullet or a shotgun style cup. 

Barrel specs: 

Outer Barrel  25 mm OD Aluminum 22 mm ID

Inner Barrel   22 mm OD Titanium 15 mm ID (seamless)





Note: they fit perfectly in the 12 G Air soft 5 rd Mags 

(STILL UNDER DEVELOPMENT)

Don't forget to try out my other designs Enjoy ;)