Yeah I've heard of story's like that and others. Even witnessed a few Remington 721's and 700's fire when taking the safety off. Just last year brand new gun did it twice for one hunter. But a gun sliding off the fender and hitting the ground who knows how hard could possibly not be the guns fault. If a fire arm hits the ground hard enough it's possible for it to go off if it's not SAFELY UNLOADED first, which most hunters would have done before propping it up against a truck before loading other gear. That would be normal in my book.