the device you’re thinking about is called rifle grenade (soldiers already carry rifles with them)
sometimes 40mm UBGL fills the same role. grenade throwing device like this would probably require different fuzes (longer delay) and it will be much less controllable than anything actually launched (you don’t want live grenades ending up nearby by accident, not an option with rifle grenades or 40mms)
the device you’re thinking about is called rifle grenade (soldiers already carry rifles with them)
sometimes 40mm UBGL fills the same role. grenade throwing device like this would probably require different fuzes (longer delay) and it will be much less controllable than anything actually launched (you don’t want live grenades ending up nearby by accident, not an option with rifle grenades or 40mms)