飞机装甲防护的发展,使得步枪弹口径的航空机枪逐渐显得力不从心,面对6—8毫米,乃至12毫米的防护装甲,小口径机载武器弹药已是无能为力。二战前夕,航空机枪显现出向大口径发展的趋势,战争进程中,许多新型的大口径机枪与航空机炮相继出现,填补小口径武器的火力空白,并逐步替代它们,在许多新编制中,大口径机枪则从一开始就成为了主要的机载武器。 Aircraft armor protection development, making the rifle caliber diameter of the aircraft gun gradually became frustrated, the face of 6-8 mm, and even 12 mm of protective armor, small caliber airborne weapons and ammunition is powerless. On the eve of World War II, aviation machine guns showed a trend toward large-caliber development. During the war, many new large-caliber machine guns and aircraft artillery appeared one after another to fill the fire blank of small-caliber weapons and gradually replace them. In many new systems, Caliber machine gun from the very beginning became the main airborne weapons.