Another reason is that it is not possible to fire accurately out of the ports of a moving IFV and access to firing ports would require internal stowage to be moved from behind the seated soldiers in the rear of the vehicle.
It is not possible to fire accurately out of the ports of a moving IFV. Another reason is this. Access to firing ports would require internal stowage. This was to be moved from behind the seated soldiers in the rear of the vehicle.