Federal ban is always possible given the right circumstance, such as a Democrat controlled congress and a anti-gun Democrat in the Oval office. It happened in 1994 under Bill Clinton and a Democrat controlled congress. They passed legislation such as the Brady bill and a prohibition on military style auto-loaders or in the vernacular of the anti's: "assault weapons". They allowed a grandfather clause because of Republican pressure, but next time we not be so fortunate. Any vote that isn't for McCain is a vote that will ensure an Obama win.
Federal ban prior to Heller sure. Federal ban after Heller never going to happen. Before Heller politicians could at least lie to themselves and voters and say it is legal because 2nd means militia and the national guard is the militia.
You, me, the people on THR know that isn't true but majority of Americans didn't or didn't care.
Heller and all the news coverage has changed that. If you took a poll today and asked
"Regardless of your personal beliefs on gun control ; do you believe the 2nd amendment
guarantees citizens of US have an
individual RIGHT to own a firearm?" [Yes/No/I don't know]
the overwhelming majority would say yes today.
I remember seeing a poll a week or two
before Heller which was worded less neutral and it said 57% believe in an individual right.
Since then the SCOTUS and all the media has played the sound bite "2nd = individual right. 2nd = individual right. 2nd = individual right" refrain a lot. Today the number might be 65%-70%.
A federal ban will not happen. SCOTUS may even invervene before it gets passed (it has happened before on other bills) and declare the bill unconstitutional before it even signed into law.
Now is some states where support of rights are lower than national average (CA, NY, IL, MD, etc) the future may be more grim, but Federally there will not be a ban.
If you don't buy weapons based on a fear of a potential future ban then haven't the antis already won. They have pushed a fear based ban w/o a vote in congress.