In response to the Sandy Hook school shootings, Sen. Dianne Feinstein (D-CA) is working on a proposed bill that would ban "120 specifically named firearms."
Sen. Feinstein hasn't released her list of guns yet, but The Atlantic Wire has created a list (below) of some of the most bannable semi-automatic weapons. By a general definition, a semi-automatic weapon shoots a round and automatically reloads.
The AR-15 is the gun that Adam Lanza used in the Sandy Hook school shooting. It's a civilian version of the U.S. military's M-16. There's a simple add-on that allows the AR-15 to fire 900 rounds a minute.
Slide Fire Solutions manufactures the SSAR-15, which allows users to simulate the fully automatic setting while holding the weapon at their shoulder. The SSAR-15 shoots three rounds at once.
The FN Five-seven carries 5.7×28mm ammunition, which is small, so the magazine can carry more rounds and the velocity doesn't decrease. The Brady Campaign has called it a "cop-killer."
In contrast, the .50 caliber sniper rifle uses huge bullets. The .50 caliber uses 13,000 ft/lbs of muzzle energy, while the AR-15 has 1,300 ft/lbs of muzzle energy.
The Barrett M82A1 can be fired while kneeling or standing, but is likely to knock newbies on their rear with the kickback.