1. Move to the gunner position on any wheeled vehicle or boat with a grenade launcher
2. Switch view mode to infrared, Zoom using the +/- on the num pad and pick a target at 1000m using the range finder
3. Use the pageup/pagedn to zero the scope to 1000m
4. Fire a grenade

Expected result is it should hit somewhere close to 1000m. It currently seems to hit at more like the 500m point or worse. As mentioned, the HMG works perfectly so please don't change that in trying to fix this one.