Brownells is taking pre-orders for LMT M203 37mm Launcher. This is very similar to the 40mm launcher used in military.
https://www.brownells.com/shooting-accessories/duty-gear/safety-amp-warning-equipment/m203-37mm-launcher-prod118458.aspxPrice is $1599. It maybe steep, but it doesn't require Destructive Device paperworks required for the actual 40mm version.
From:
Soldier Systems Daily