While in reality the Beretta M9 is the standard issue sidearm for the US military, the Beretta 92FS is the weapon seen used in the series by the US military personnel. The handgun is used by Commander Harmon "Harm" Rabb, Jr. (David James Elliott), Lieutenant Colonel Sarah "Mac" Mackenzie (Catherine Bell) and Rear Admiral A.J. Chegwidden (John M. Jackson).
Colt M1991A1
In "A Separate Peace, Part 1" (S6E07) and "A Separate Peace, Part 2" (S6E08), a Colt M1991A1 (used due to its similar appearance to the more accurate M1911A1) is used by a young Lieutenant Tom Boone in a Vietnam flashback.
Makarov PM
The Makarov PM is used by several characters in the series.
Shotguns
Remington 870
Submachine Guns
Uzi
Men sent to ambush a prisoner convoy are armed with Uzi's in "Salvation" (S6E19).
Rifles
AK Variants
Kalashnikov and Norinco Rifles have been seen during the show's ten seasons.
Norinco Type 56-1
Harm and Capt. Alex Volkonov (Alexander Kuznetsov) are seen using Norinco Type 56-1 rifles with slanted muzzlebreaks to repel Chechen rebels in "Legacy: Part 1" (S6E08).
AKMS
South Vietnamese troops is armed with AKMS rifles.
M16SP1
M16's are frequently seen in the flashbacks to Vietnam, such as in the episodes "A Separate Peace, Part 1" and "A Separate Peace, Part 2."