People seem to really dislike rifle grenade spam, and considering how quick you can reload them, I fully understand why. A really good way, at least in my opinion, to fix this would be to extend the operation of them to reflect how they work in real life.
Rifle grenades, back before things like the M203 replaced them, required a bit more effort when loading and reloading them. Unlike in enlisted where you just shove the grenade onto, or into, the launcher and fire, you needed to open the bolt, insert a blank cartridge, close the bolt, and then you’re ready to fire, at least depending on the grenade. Some grenades need to have their pin pulled first. Which also leads me to the secondary point that the American grenade launchers using MK2 grenades and the British cup discharger, which uses unaltered Mill’s bombs btw, should not explode on contact, they should work like normal hand grenades.
But the main point is still that rifle grenades should take a lot longer to use compared to how it is in the game currently. So doing this would kill two birds with one stone: Rifle grenades get nerfed, and the history nuts get what they want as well.
The Dyakonov grenade launcher uses live cartridges to fire its grenades, the Type 100 grenade launcher on the Type 38 also uses live ammo to fire standard hand grenades.
Grenade launchers dont need or use ammo of any kind to be fired in the game, but I havent used them in a very long time so I dont know if it was fixed, I doubt it was though.