Bison Under Maintenance a fantastic build from modelling friend Jaffe Lam 

The 15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B, sometimes referred to as the Sturmpanzer I Bison was a German self-propelled gun used during World War II

The Invasion of Poland had shown that the towed sIG 33 guns assigned to the infantry gun companies of the motorized infantry regiments had difficulties keeping up with the tanks during combat. The easiest solution was to modify a spare tank chassis to carry it into battle. A sIG 33 was mounted on the chassis of the Panzer I Ausf. B, complete with carriage and wheels, in place of the turret and superstructure. Plates 13 millimetres (0.51 in) thick were used to form a tall, open-topped fighting compartment on the forward part of the hull. This protected little more than the gun and the gunner himself from small arms fire and shell fragments, the loaders being completely exposed. The rearmost section of armour was hinged to ease reloading.

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