It was used by the dismounted Infantry . With only a 2 man crew in the 251 , hard to use guns at both ends of the vehicle when one guys driving . There are pictures ( which I will try to find ) of the rear gun with bi pod , sort of strapped to the rear mount and the front gun hard mounted in a frame to the forward shield mount , with out a bi pod . Of course , just like in the Panzers , a bi pod was carried so that if you had to bail out of the vehicle, taking the gun with you , you could use it .