The whole fireing system is designed for the fireing pin to fall on a primer, when it doesn't then things go wrong. The fireing pin is designed to be stopped by the collision with the primer, when that doesn't occur then it is stopped by something else, like the return spring, or the sholder of the fireing pin, or the rim cut on a rimfire rifle. None of these are good things to have happen. Why would anyone dryfire a gun anyway? Didn't your father teach you anything? Larry