Bomber gunners: Snipers?

[IonicRipper]

I'm on the 3rd mission of the CoD campaign (the one where you and your flight leader have to shoot down a damaged He111.) I've tried this mission 2 times and every time i get anywhere near the bomber, its gunners chews my plane out like i'm target practice. The first time i admit i did it wrong as i was just staying on its tail to try and land clean shots. The second time i came from the side with good speed and i still managed to get destroyed. To me it feels highly unrealistic that the gunners are THAT effective. Its also very frustrating to say the least. Is there any way to reduce the effectiveness of the gunners to a realistic level?