Originally Posted by DJ's left nut
That's great. It's also probably bullshit.
A soft-jacketed bullet isn't going to spark at all and the spark from a FMJ round isn't going to be hot enough to ignite the fuel (and you'd have to hit the tank at just the right angle to make a spark at all). Moroever, the gas would have to be at exactly the right fuel/air mixture to actually ignite.
There are ways you can rig it to make it blow...and you can title a YouTube video about damn near anything you want. But in the end you just have to kinda turn your brain on here and think about it.
There isn't a catalyst. There isn't going to be an explosion.
EDIT: This isn't dispositive on it's own, but it's a hell of a lot more dispositive than a 14 second clip of a guy shooting something at something and making fire.
Yeah, that's where Mythbusters was trying to show that the stunt from Casino Royale wouldn't work in real life. That you aren't going to shoot the pistol that Bond used and pierce through a propane tank. A high powered rifle round will though. A full tank will blow out enough propane to flood a room when pierced. I have no idea where the tank was within the structure, or how full it was, or if the guy was even telling the truth when he said that there was one in there. But if the tank was in there, and it was reasonably full, it could have been pierced by weapons that were on scene. There are a number of ways that the resultant cloud of propane could have been ignited at that point. If you "turn your brain on and think about it" as you suggested, it's silly to just assume that the authorities torched Dorner based on one comment made by a passing cop.