Its fine, presuming its sufficiently rare that it is never used. Its way too good now if it ever gets used.
Dropping it down to somewhere in the region of twice as good vs BA as a .223 pistol would mean its still really great, its just not so increadibly great that it makes all other weapons look like pea shooters.
I've been working on a price system for weapons the last few days, which generates a price based upon their power vs different armour types, the range and a couple of other things. The Avenger comes out at $6350, the Sniper Rifle comes out at $5000, a buffed Gatling comes out at $5450, a nerfed Gauss Rifle comes out at $8800 (most expensive thing) and an unnerfed Gauss Rifle comes out at $11100 (!).
If you had a small chance of finding a rifle per hour (say 1 in 150) and a little higher of a pistol (say 1 in 75) with sufficiently hard work to do to even have a chance ... then you won't really be swimming in gauss. Could also limit it to between 10-50 rounds spawning in the whole of the glow per hour.
As namenot says, alts farming the stuff isn't great.