I have actually told a customer their gun was out of whack, told them I took it apart everything looked great from inspection. I shot it and works fine and then proceeded to tell them I have no idea why it did what it did, they were happy it was working and the gun hasn't had any more problems but he was a little irritated when he still had to pay me. Now I also told him it is happened again I would fix it for free, I would only charge if for some unforeseen reason I needed to order parts.