All weapon velocity is 2150 m/s (after 7.5% velocity quirk) for quick and accurate range shooting. Treat the AC2s like a single shot weapon only shooting with the gauss rifle, this way your ammo will last and you'll make the most out of every volley. Close-range you will need to fire faster of course.
For the purpose of the DPS in short range, but the ability at long, I agree. However, for the purpose of sniping, it takes 24 tons worth of ballistics + ammo to increase your alpha from 30 to 38.