M3 'grease gun' manufactured in large quantities during ww2 for distribution to US soldiers as an alternative to the costly Thompson submachine-gun( interms of its use of materials and its large number of manufacturing steps), its heavy weight, consisting almost all of steel with a stamped body, and its low firerate gave it very good accuracy with low recoil.
This particular model is not entirely accurate in relation to the origonal M3 and is my depiction of a replica by people in a post apocalyptic setting.