1884年,英籍美国人海勒姆·史蒂文森·马克沁设计的世界上第一挺利用火药燃气完成射击循环的机枪获得发明专利,其标志着自动武器新纪元的开启。不过,这种新的原理也带来了如何为武器散热的问题——即无论采用何种火药作为动力源,其能量将有很大一部分以热的形式转移到枪管等金属零部件上。即便是早期以黑火药为动力的枪弹,在发射瞬间,枪膛内部的最高温度也将达到1500℃,而无烟发射药燃烧时会超过3000℃。在这样的瞬时高温轮流冲击下,枪管会迅速变热,一般不间断发射200发以上,口径就会膨胀、射程变近, In 1884, the first U.S.-designed machine gun designed by Helm Stevensen to win the shooting cycle with gunpowder gas was patented, marking a new era in automatic weapons. However, this new principle has also brought about the issue of how to heat a weapon-that is, whatever type of gunpowder is used as a power source, a large part of its energy will be thermally transferred to a metal part such as a barrel. Even bullets powered by black gunpowder were fired at an instant, the highest temperature inside the chamber would reach 1500 ° C while the smokeless propellant would burn more than 3000 ° C. In such an instantaneous high temperature rotation impact, the barrel will quickly become hot, usually more than 200 rounds of continuous launch, the caliber will be expanded, the range is close,