I don’t know how rifle grenades were/are used, but my impression is that they were/are generally not shoulder fired , but fired from a mortar-like position with the butt stock against the ground.
After the match I just had facing an enemy team who were either jumping about firing rifle grenades, or just launching a sustained barrage for what seemed like long enough to clear a point, and then cap it, and still have a couple left to launch at the soldiers who were retreating; I think something needs to be done to bring them to heel, a bit.