That's really only an issue with free float firing pins and it takes a serious impact for it to be an issue. Were talking Ithaca 37s, Winchester 1897s etc. Anything of recent vintage with a firing pin return spring is going to have to be dropped from an unrealistic height and land on the muzzle. The bigger issue is that pretty much everyone uses some sort of trigger block as a safety. If the sear or hammer is released due to an impact there's no safety device to stop the hammer from hitting the firing pin and no safety to stop the firing pin from striking the primer.
The double action models were essentially drop safe.
"It's surprising how often you start wondering just how featureless a desert some people's inner landscapes must be."
-Maple Syrup Actual
When I was taught to carry and use a shotgun, I was told that "cruiser ready" meant 1) chamber empty, 2) hammer cocked, and 3) action closed. This has the advantage of locking the forearm so that the action will not open from vibration that is surely encountered in patrol vehicles. This is how I store my shotguns in the safe, so that the actions remain closed. Another advantage is that one needs to hit the action bar release to load the chamber. Interestingly the safety was never discussed in reference to "cruiser ready" but I followed the above quoted post out of an abundance of caution.
Most shotguns are definitely not drop safe, including the Remington Model 11 and 870, as the safety only blocks trigger movement. That is why hunters are taught to unload when crossing fences as dropping an 870 from waist height is enough to jar the sear enough to release the cocked hammer. I have verified to my own satisfaction with my 870P models that a three-foot drop is enough to cause the gun to fire. If you pull the trigger plate from an 870, it is easy to see the 870 is not drop safe.
Last edited by farscott; 07-22-2016 at 06:34 AM.