I don't think it is exactly fair to say the buff guns are "overmodeled". I don't think that they are any more, I have used that .target function EXHAUSTIVELY to prove to myself that they are the same as the 'fighter' .50s.
I did the following-
Took a B-17, put the .target at various ranges out to max range (which was 1400 yards and some change), and fired ONLY the nose guns (which are the two cheek guns and the nose turret). Now, this is a tad a-historical, because the navigator could only man one cheek gun at a time, but this is a minor point. I took some screenies (which are deleted now, but it is an easily reproducable test). I then took a P-38, and used the 4 guns in the nose on the .target at various ranges, out to max range (which was, coincidentally, ALSO 1400 yards and some change). The dispersion patterns looked identical in all cases except for VERY short range (where each gun actually leaves its own seperate pattern, under 100 yards). Now, correct me if I am wrong, but a bullet will have a 'set' kinetic energy when it leaves the barrel of a gun, right? And it uses that energy up to fly through the air and punch through some thin metal called an enemy plane. If both the fighter AND the bomber .50s had the SAME max range (1400-odd yards to the front), AND the same dispersal pattern- then they are identical AND would hit at the same power, right?
Now, I also did this test with the rear guns of a B-17 (which are the same as on the B-26). The Max range was 1800 yards and change. Now, it may seem that HTC has artificially extended the range of the guns- BUT... I will try to explain this as I see it.
The reason that the forward firing guns can only travel 1400 yards and change (to hit a target that is moving away from you at the same speed you are moving), is because they are actually travelling the same distance that the rear guns bullets are travelling to hit a target that is 1800 yards away but moving towards you at the same speed you are moving. The rear guns also probably hit harder since you are travelling INTO them, thus allowing them to keep more of their energy for going through you, rather than going through the air trying to get to you.
Now, this doesn't mean that there is NOTHING wrong with buff guns. I believe that the firing arcs need to be revamped, and that either the gunners should be able to shoot off parts of their own plane or not be able to shoot through their plane to hit you. I also think that .50s in general hit a bit to hard, but that may be because of HTC's 'all or nothing' damage model, where each round that hits you appears to take away a certain number of 'hit points', and when that total is exhausted you are dead.