the anti aircraft gun...

I disagree. Here is why...

For starters, Thunderbolt explains that they don't go through the door. He diagrams why on the dusty hood of the car. They go through a side wall which is nothing more than poured concrete and rebar. Second, they use armor piercing shells in the cannon. Third, if you watch the film, they're only a couple of feet from the wall and it took like 4 shots to create the hole. I think 4 shots at point blank range with a cannon loaded with armor piercing shells is going to make mince meat of concrete & rebar wall.



I don't want your watch, man. I want your friendship! - Lightfoot