Grenade launcher ? I'm not really sure I want a grenade launcher.
About 15 years ago, I thought a 37mm flare launcher would be fun. So I bought one and attached it to my AR. It looked kind of cool and impressed some non-gun friends. I never used it for anything - just a lump of steel weighing down the barrel of an AR I never used either.
So, I recently removed the "grenade" (flare) launcher. I forgot that this particular one (don't know the brand) had a steel (un-rifled) tube, not one of the aluminum tubes) Anyway, tastes change - not into grenade launchers anymore.