As mentioned, hitting the other plane with a concentrated burst is important, as is hitting at convergence, and hitting in a particularly vulnerable spot helps too. Also realize that ballistic effectiveness drops with distance, so bullets have more "killing power" close up and less at longer ranges. Stretching your convergence point further out does not make your guns more effective at longer range. It's far better to get in close for a shot, and be in a position to "hose him down" for 1/2 second or so.
By close I mean D200. Once in a while I'll shoot at D400, and seldom do I shoot as far out as D600. The only real times I shoot at D600 is on someone I need to "scare" into turning, so I can catch him. I keep my convergence set at 275, which is the most effective I've found for my style of fighting. As I close on a potential victim, as the counter switches from D400 to D200, the actual distance is 299 yds. Allowing for the fact that I'm closing (catching him), and need a second to solidify my aim, my shot distance at that point should be right at my convergence... This maximizes the effectiveness of my bullets, at a range where they still have plenty of "punch", and the target is plenty big to see and hit.
As for hitting a vulnerable spot, you'll do better when you start to aim at a particular point on a plane, rather than just trying to hit the plane in general. 50 hits scattered across the plane is not as effective as 50 shots in the base of the right wing, for example. The most vulnerable spot on a fighter is the top of the cockpit (IMO). So I make the cockpit my primary target. Knowing that I have a tendancy to hit slightly behind where I want to hit, I try to hit a spot 1/2 way between the cockpit and the prop on the enemy fighter, any time I have the opportunity.
This gives me a pretty high allowance for error on my part. If I hit my target at that point, or ahead of it, I'll cause an oil leak or kill the engine outright. If I hit behind that, I kill the pilot with just a few pings, and any further back and I chew his tail off. If I miss the fuselage entirely, by aiming where I do I open up a good chance of wrecking one of his wing roots, or at worst taking one of his wingtips off.
On bombers try to hit the cockpit, a wing root, an engine, or a wingtip.
MtnMan
