Now Playing: 1-25-13 Marketplace

David Gura pays a visit and reports from inside a Virginia gun store. Twitter’s newest service lets users post six-second videos, but some are complaining that's too short. Apple's latest supplier responsibility report goes deeper than ever into its Chinese supply chain. We look into whether the legal costs in the fight between Barbie and Bratz has been worth it. The European Union’s market for carbon emissions credits is crashing, but the EU isn’t ready to bail it out. And Las Vegas oddsmaker Jimmy Vaccaro talks about proposition bets related to the Super Bowl.