An M4A1 carbine can be briefly seen in the hands of a Secret Service Counter-Assault agent in the initial scenes.
Remington 700 PSS
A Remington 700 PSS can be briefly seen in the hands of a Secret Service agent after Garrison's escape, and in the hands of a Secret Service Counter-Sniper on the roof of the building in Toronto.
The Assassin (Jasmin Geljo) uses a suppressed Beretta 92FS at the Allenwood Mall to shoot Pete Garrison's shadow.
SIG-Sauer P228
Sig Sauer P228 9mm pistols are used by all the actors portraying US Secret Service agents, including Agents Pete Garrison (Michael Douglas), David Breckinridge (Kiefer Sutherland) and Jill Marin (Eva Longoria). Note: The real firearm used by the US Secret Service is the SIG Sauer P229 .357 SIG. I would suspect Hollywood to use 9mm blanks since .357 SIG blanks seem harder to find. And since the real Secret Service Agents were using 9mm, P228's are more abundant than P229's in 9mm I think.)
H&K MP5A3
The H&K MP5A3 can be seen in the hands of a Secret Service agent after Garrison's escape, as well as in the hands of one of the disguised assassins.
H&K MP5K PDW
Secret Service agent Aziz Hassad fires the H&K MP5K PDW during the assassination attempt.
Taurus PT92
One of the assassins carries a Taurus PT92 when he is shot by Garrison
Glock 17
Glock 17 pistols can be seen in the hands of an FBI agent as well as in the assassin's apartment. The latter looks like a second generation.
Unidentified shotgun
An unidentifed shotgun is brandished by an FBI agent when they stop Pete Garrison
I'm not sure, but the pistol grip seem to be the tipical enlongated grip of a Ithaca 37 "Stakeout". Lone Soldier 10-29-2009, 10:28
Unidentified shotgun
An unidentifed shotgun can be seen on a rack in Xaver's mother's house.
Unidentified revolver
Not sure what this revolver is. It can be seen in the assassin's apartment.
S&W Model 60, with a 2 1/8" barrel and non-standard grips maybe?