A hand-driven machine gun, the Gatling gun was the first firearm to solve the problems of loading, reliability, and the firing of sustained bursts.
早期的盖特机炮虽然要靠手摇才能开火，但它毕竟是同时解决了装弹、稳定性、连续开火问题的首款火力武器。
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PowderMed caught Pfizer's eye because of its nifty helium-powered, hand-held device that delivers vaccines by firing DNA-laced gold particles into the skin.
The intention of this article is to analyze the distinguishing features of motion of hand-held shoulder arm under firing and to introduce a feasible system for measuring this motion.