Honestly, I would hang on to it. If you're not desperate for money, it's better to hang on to it. If an AWB of any form passes, Grandfathered guns will be worth their weight in gold. If you need something down the line, you don't have to worry because you have the pre-ban lower. OR, if there's a ban, the value of the rifle will skyrocket.
Now, if you do want to sell it for money and take advantage of this frenzy, you should be going for paydirt. If you're gonna price-gouge, don't pussyfoot around; really gouge the **** out of it. Start at $3000 or $3500 or something like that. Leaves room for bargaining, but it also opens the door for some desperate numbnuts to scoop it up at your price. Given the panicked state of the market, you can really play some games and probably convince someone to give you some ridiculous amount of money.