Complex sentence: It has also been stated that the weapon was fired by grasping the stock near the trigger, like a pistol, while the curved portion is tucked under the shooter's forearm, allowing the rifle to be fired with one hand while mounted.
Split into simpler sentences: It has also been stated that the weapon was fired by grasping the stock near the trigger, like a pistol, while the curved portion is tucked under the firers forearm. This allowed the rifle to be fired with one hand while mounted.