《天工开物·下篇·佳兵》
鸟雀在三十步之内中弹，会被打得稀巴烂，五十步以外中弹才能保存原形，到了一百步，火力就不及了。
鸟雀遇于三十步内者，羽肉皆粉碎，五十步外方有完形，若百步则铳力竭矣。
Birds and sparrows hit within 30 steps will be beaten to pieces, and those hit beyond 50 steps can be preserved in their original form. When it reaches 100 steps, the firepower will not be enough.