Here's a British poster from a series that were made during WWI to show correct flying/combat methods. Sorry for the bad pic, as I took it in the low light at the USAF Museum.

Is it possible to kill the gunner? I swear, I've poured enough lead into that rear seat to turn the little ingrate into a pasta colander, and he still keeps firing back.

That's a classic WP!

Yes is it possible, but sometimes I think from damage point of view that gunner is just as small as golfball