gunners
There are a couple of variables that need to be adjusted. First as was stated, the ratelimit speaks to how quickly the turret turns and hence the accuracy the turret gunner has. Second, the bullet has parameters that limit the range at which the gun fires. The problem is that the bullets in our planes did have a range of 700 meters, but no pilot or gunner usually fired at that range. I have read that pilots attacking bombers did open up at around 500 meters since the allied gunners with the 50 cal could reach out and touch the attacking planes so this is an issue. But really hitting a plane at 500 meters was the "golden beebee". I made a set of guns/weapons for night fighters that had a range of 150 meters. Why - since this was the range reported by pilots and gunners that they used during combat. It makes the game more realistic as all hell breaks loose when you get close and at 150 meters, the turret gunners are very accurate.
So if you don't want 700 meter engagements, change the variables that control the gun range. I think that the weapons folder is the place that you can change the range- just don't remember. Also, health, eyesight parameters too as well as the AI settings. These all can be tweeked to make the game the way you like it. I set up the eyesight parameters to reflect the range on the radar screens for nightfighting, that is most radar was able to see out 6 km (German) so by revising the pilot attributes you can change when objects appear on the radar screen. I also believe that this effects pilot performance in other ways as well. Health also effects eyesight and engagement range too.
Have fun!