It's not about making a pretty similar copy in terms of weight and balance. OP is asking about a weapon so superior it was viewed as magical. Let's think about

It's not about making a pretty similar copy in terms of weight and balance. OP is asking about a weapon so superior it was viewed as magical. Let's think about this in terms of the standard engineering design-V: if you have nobody available for validating the design, how could you produce a product that you know to be so technologically superior that it appears to be "magic"?