During WWI the stokes mortar was produced by the britsh and later accepted by the US. The 3in Mortar was made with a WP and HE filler the practice round was filled with sand with lead plug instead of fuze. The 4in stokes was produced in HE, WP, and Chemical such as mustard and ammonia gas. The Stokes mortar could fire as many as 22 rounds per minute and had a maximum range of 1,200 yards.