What is the make of a gun with serial number 40057?

Answer 1

That is impossible to answer. If we knew the manufacturer and model, the serial number MIGHT be useful to find additional information, but you cannot find the manufacturer by the serial number. A few manufactures have used a single serial number sequence through many models, but most have began each model with serial number 1, so the same number may appear on hundreds of guns from the same manufacturer. Before serial numbers were required, some makers used "block numbers" which would re-start at 1 each time it reached 1000 or 10000, so the same number could appear on several identical guns. Your gun can probably be identified if you will list all the other things written on it.