The massacre at Newtown, Conn., last month brought long-running debates about gun control back into the spotlight. And with them came renewed volatility for gun stocks. The two pure-play gun makers on the market, Sturm Ruger (RGR) and Smith & Wesson (SWHC), were already teetering in early December. Both companies did very well in 2012, as the possibility of re-election for President Obama led to a surge in gun sales among fears of tighter gun