Medieval Song Chinese Crossbow

This is my reproduction of a Divine Arm Chinese Crossbow 神臂弩 orignially from the Song Dynasty Military. Also known as Shen Bi Gong (神臂弓, lit. 'Divine limb bow'), Shen Bi Nu is a crossbow design inherited from Song Dynasty and the first truly military grade crossbow in the Ming army. The name Choice with exaggeration Is Typical of the Time. Ming Dynasty Shen Bi Nu is around 120lb or more depending on grade, while the Song Dynasty Shen Bi Nu is around double the weight. Unfortunately due to bow restrictions I cannot find a bowyer who can make a 240lb@24 prod at the moment yet. This bow prod is 119@24 or 144@28 From the Song source Cui Wei Xian Sheng Bei Zheng Lu: ──神臂弩：桩牙里一尺八寸，葫芦头四寸，镫二尺，桩长二尺三寸，角檐长四尺五寸。 Divine Arm crossbow: Within stock teeth 1 chi 8 cun, gourd head 4 cun, stirrup 2 chi, stock length 2 chi 3 cun. Horn prod length 4 chi 5 cun Also "If the prod is longer than 6 chi and if the stock is longer than 3 chi(38.8 inches), then at the shoulder the crossbow prod will tip toward the ground, and below there is the problem of tripping, when stepping on such a crossbow the stock head will reach the chest, so above there is no pulling strength…… At present day we want to use crossbows with draw strength of 2 stone to 3 stone (~264 lbs to ~397 lbs)…… The crossbow prod should be 5 chi(1.6 meters) to 6 chi(1.9 meters), and cannot be too long, so that short soldiers can easily shoot it at the shoulder. " (Cui Wei Xain Sheng Bei Zheng Lu) They were expected to shoot and then probably either retreat behind rows and rows of infantry at the last moment, or have the infantry behind them advance forward to protect them: See Goose File formation from the Wujingzongyao with crossbowmen and archers shown at the very front Special thanks to HackneyedScribe for the help with research and guidance