The Sturminfanteriefeschuetz 33B (StuIG 33B) was a German assult infantry gun of the WW2. The StuIG 33B was based upon a Panzer 3 chassis, with the turret removed and mounted with a 150 mm StuIG L/11 gun and an 7.92 mm MG34 machine-gun. The StuIG 33B was manned by a crew of five and powered by a Maybach HL120TRM engine providing a top speed of 20 kmh and a range of 110 km.
As 6th Army drove deeper into Stalingrad maneuver became impossible and the Wehrmacht's vaunted Blitzkrieg tactics devolved into a vicious house to house, hand to hand struggle requiring brute force rather than finesse. A special mobile assault vehicle was needed engage the enemy at point-blank range with high accuracy. Because German and Soviet soldiers sometimes occupied different floors of the same building, fought in close proximity only a few yards away in cellars or behind the debris of smashed walls absolute precision was required. The StuIG 33B with its 15cm (5.91-inch) heavy infantry gun, artillery sights and fully enclosed fighting compartment provided a nearly optimal solution.
On 20 September 1942 the Waffenamt (WaA) or German Ordnance Department ordered twelve self-propelled artillery vehicles mounting a 15cm L/11 howitzer for immediate production. Based on the StuG III Ausf E and F/8 chassis they were officially designated the StuIG 33B. Intended to aid in the close-quarter combat of Stalingrad the 15cm weapon was capable of demolishing a house with two or three rounds. The first twelve were assigned to Sturmgeschutz Abteilung 177 and 244 and fought with distinction through some of the worst fighting on the Volga.