I think this give one gives a good idea what it was like. It was one DANGEROUS situation to be in. I think half of all B17's made were shot down. Those cannons the Germans had ripped them to pieces and those R4M Rockets late in the war were even more devastating. I wouldn't want to be in one.
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Some German General figured out fairly soon that they would lose the war. Said something like “We shoot one of their planes down, and they send 7 more to replace it!”
Of course lots of young men were also shot down. RIP.
The first part was German gun camera pics, the last hairy one was from a post-WWII anti-aircraft missile test.