..Manned gun positions, with the exception of shore batteries and heavy cruiser batteries, are intended to be utilized to perpetuate fights between airfields that would otherwise only last a fraction of the time. Field guns are also extremely fragile, one cannon round anywhere near one kills it. Manning one, is really an altruistic public service, a benevolent contribution of time purely for the betterment of gameplay. The only tangible reward, other than the satisfaction of helping perpetuate fun fights for others, is the fleeting 10 seconds of fame offered in the text buffer after a single cannon round or mg burst from a vulcher takes out your gun. The vulcher's reward for taking guns out, may not be a kill on the gun itself or the denial of the gunner's kills, but it is a 'free pass' to vulch his countrymen with impunity.
Shooting crap is its own reward, indeed, IMHO, the ONLY reward, in AHII.
But the way FGs are setup probably keeps people in 'em and firing "until the finish", which is a good thing.
Funny story related to that: Last night, I dove on a single flak parked by the maproom in flattened town, in my P-47, to make way for the troops. He took off my wing at precisely the same time I released my bomb.
I didn't get any "XXX shot you down" message. Apparently he towered out on the off-chance my bomb would actually hit him, managing to deny himself the kill on me on top of giving us the base.
