Complex sentence: The turret was armed with a 57 mm main gun with a 6.5 mm machine gun mounted in the rear of the turret and another mounted in the front of the hull.
Split into simpler sentences: The turret was armed with a 57 mm main gun and a 6.5 mm machine gun mounted in the rear of the turret. There was another 6.5 mm machine gun mounted in the front of the hull.