Hand grenades have a range limited to 40-50 m, so various contraptions have been invented to launch them further. The Croatian Krešimir grenade launcher is one of the most bonkers of the bunch, using a blank cartridge to propel hand grenades with percussion fuses and no safety pin.

The video details all the things that can go wrong, so I wanted to make a safer variant of this design, keeping the safety pins on until just before launch. The internal piston is based on the Canary noiseless grenade launcher system and allow to use non-cylindrical grenades as long as they are encased in a foam or plastic sabot.