So after looking through many of my images I found this, it is ammo that can be used in the mortar... can't believe it
The actual ammo is not live and will not explode, it can't be used either. This particular one looks really strange compared to the others. More stats on it displayed in the picture.
Sometimes the stats and description which is given on the sign I question, I would really love to see what gun this ammo can actually fit it, More stats above.