A properly manufactured and maintained gun of "modern design" (which includes, for example, the 1911 as in that was the year the US Army adopted it), if its con

A properly manufactured and maintained gun of "modern design" (which includes, for example, the 1911 as in that was the year the US Army adopted it), if its control surfaces (safety, trigger) are secured by a proper holster or the like, is pretty much not going to fire as long as you keep it away from a fire or a MRI's very strong magnet. Still, if your loaded gun is being discovered by the TSA in this fashion, you're violating Rule 2 of gun safety (https://en.wikipedia.org/wiki/Jeff_Cooper#Firearms_safety https://en.wikipedia.org/wiki/Jeff_Cooper#Firearms_safety) and of course you might not know until it's too late that your gun has a manufacturing flaw, you screwed up maintaining it, and there are no doubt many old guns out there with marginal designs.