Blurry photo and worn down to nothing. I'll take a WAG that it is an As of Nero based on the shape of the top and back of the head.
I agree it looks like Nero, but I can't make sense of the obverse legend. From the photo it looks like it contains "AVG P AV" but that can't be right! Seems like it might be identifiable from that bit of legend, though. Maybe play around with possibilities at this site: http://www.jhecoins.com/obverselegends.htm .
Try AVG F AVG which is the standard way of expressing 'of the Augustus son Augustus' or 'I am the emperor and son of the emperor'. There are only so many candidates for this formula so you can rule our people whose father was not emperor before them.
Yeah, it's gotta be Tiberius. There are a bunch of examples where the positioning of "AVG F AVGVSTVS" is just right. See Wildwinds: http://www.wildwinds.com/coins/ric/tiberius/i.html I even have one myself!:
Believe it or not, I was going to say the shape of the bust reminded me of Tiberius, butI had nothing else to go on. So good on ya.