I know an fast and great way to destroy formations of bombers without give a shot, all you have to do is:

1- get the fw190.

2- when you spot a big formation, no matter what position they are comming, (neutral, side or offensive) you have to get positioned and trow one stopwatch rocket at 3500-600 of distance, if you trow it right you can shot down at least 2 bombers and injuried one.

3- pass trought the formation carefully, and run away from escorts, turn and do the same method, trow another stopwatch rocket and overpass the formation again, trying to advoid shots, do it and eat more 3 bombers.

one time i shot down 15 b17 bombers and the rest of the bombers was shot down by the AI 190s,109s, i highly reccomend to pull down the airplane and pass under the formation far away from the defensive fire, so you gain speed and  can make the deadly bomber nightmare party he he he.