I have another tactic that works most of the time. If you are 1 vs 1 with a bomber and no other friendlies or cons are around, just park your fighter about 1.5 k behind the bomber. 80% of the bomber gunners will shoot at you all day long, even though they are either out of range, or doing VERY little damage. After about 20 seconds, they should be about out of ammo, then creep a little closer and fire away.
Obviously this isn't as safe or effective a tactic as the first one I posted, but sometimes there's no way you can get alt on a bomber at 30k. At the very least a bomber without a gunner can't even think about bombing until you are gone. (No need for this if the bomber is a b26, just dive below him and pull up into the blind spot.)
bloom25
THUNDERBIRDS