It seems he is going after universal background checks and Standard Capacity magazines (which he calls Hi Cap).
http://www.reuters.com/article/2013/01/10/us-usa-guns-idUSBRE9090YM20130110
http://www.usatoday.com/story/news/politics/2013/01/10/biden-nra-wildlife-gun-control/1823511/
http://www.reuters.com/article/2013/01/10/us-usa-guns-idUSBRE9090YM20130110
http://www.usatoday.com/story/news/politics/2013/01/10/biden-nra-wildlife-gun-control/1823511/