Alan Patterson of Tennessee tries out a rifle scope next to a military poster at the Leupold Tactical Optics booth at the National Shooting Sports Foundation's 33rd annual Shooting, Hunting and Outdoor Trade (SHOT) Show at the Sands Expo and Convention Center January 18, 2011 in Las Vegas, Nevada.

An industry retailer examines various SIG SAUER sport rifles at the National Shooting Sports Foundation's Shooting, Hunting and Outdoor Trade show, Tuesday, Jan. 18, 2011 in Las Vegas.

Two Glock 26 hand guns lay on a bed of empty shell casings while on display at the Shooting Hunting and Outdoor Trade show, Tuesday, Jan. 18, 2011 in Las Vegas. (AP Photo/Julie Jacobson)

John Francis of California checks out a grenade machine gun at the Heckler & Koch booth at the National Shooting Sports Foundation's 33rd annual Shooting, Hunting and Outdoor Trade (SHOT) Show at the Sands Expo and Convention Center January 18, 2011 in Las Vegas, Nevada. The shooting rampage in Tucson, Arizona on January 8 that killed six people and injured 13 people, including U.S. Rep. Gabrielle Giffords (D-AZ), has sparked debate about gun laws in the media and Congress.

Smith & Wesson hand guns hang on display at the Shooting, Hunting and Outdoor Trade show, Tuesday, Jan. 18, 2011 in Las Vegas.