The Day the Earth Stood Still (2008)The Day the Earth Stood Still (2008) - Internet Movie Firearms Database - Guns in Movies, TV and Video GamesThe Day the Earth Stood Still (2008)
The Browning M2HB heavy machine gun is one of the most commonly-seen weapons in the movie, mounted on many of the Humvees and other U.S. Army vehicles seen throughout the film.
M16A4
Most of the U.S. soldiers in the movie use M16A4 assault rifles which have had the removable carry handles left on (instead of removed to attach optics, as per the norm in the U.S. military).
M4A1 Carbine
Some of the U.S. soldiers in the movie also carry M4A1 Carbine assault rifles fitted with various accessories from the SOPMOD kit.
Glock 19
When Klaatu's (Keanu Reeves') ship first arrives in Central Park, the NYPD officers at the scene are armed mostly with Glock 19s.
Remington 700
The NYPD ESU snipers who cover Klaatu's arrival at Central Park are armed with Remington 700 rifles with fluted barrels and some time of enormous night-vision sight.
SIG-Sauer P226 (?)
When Klaatu is being interrogated, a U.S. soldier guarding him has a pistol in a thigh holster which appears to be a SIG-Sauer P226, though this is not certain.
Beretta 92FS
The police officer who tries to arrest Klaatu is armed with a Beretta 92FS.
DefTech 1315
In the news footage of rioting seen on the TV, a riot police officer is armed with a DefTech 1315 which he fires at a group of rioters.