Congrats on having the foresight to hang about with a quick of hand and excellent eye/hand coordinated woman.
Does she shoot? Does she shoot better than you?
Is she Irish? Just kidding.
Tell your customers to buy something cheaper for their kockamamy experiments, something quaint and American, like an LC Smith or a Stevens 311. Add lead, duct tape, rocks, etc. until they are or seem content that whoever built the first (English) example, knew what they were doing.
If that doesn't do the trick, take their money.
Best,
Ted