Golgo 13 hijacks an airplane bound to America with a Sky Marshal's Glock 17. Hijackers used this as their main sidearm during the hijacking on an Air British flight. Jose uses this as his main sidearm after escaping from the police.
M1911
Duke Togo aka Golgo 13 uses a suppressed M1911-type pistol during one of his missions.
Unknown M1911 variant
Used by Brigitta at a pistol firing range.
Note- Looks more like a Beretta 90-Two
Sig Sauer P229
An American Coastguard member has the P229R DAK pistol since it's their main sidearm.
Sig Sauer P230
J.J. uses this as his sidearm in "The Glass Fortress" to wound Doherty after he finds out that his daughter was killed prior to an organ transplant.
Smith & Wesson M36
Used by Golgo 13 as his main sidearm. In the show, it seems to be either a 2 inch Model 15 or a 14 judging by the Baughman Quick Draw like front sight sight and adjustable rear sight.
Walther P5
Pamela is seen with this in the eyecatch only.
Submachine Guns
Heckler & Koch MP5
Used by Shadow to snipe down American Coast Guard officers despite having a storm and that SMGs aren't good sniping platforms.
Heckler & Koch MP5K
Used by gunmen to attack Golgo 13's motel room in Santa Anna.
Heckler & Koch MP5SD
Used by SWAT officers in San Antonio, Texas to intercept the hijacked van. What kind of SD submachine gun is unknown as the buttstock/fire selector is not clearly shown.
Assault Rifles
AK-47
Encountered by Duke during one of his missions.
Colt M16A1
Used by AX-3 during a joint mission before he tried to turn his weapon against Golgo 13. Used by a mercenary before Kaizer throws in the air to let the Savine brothers destroy it.
Colt M16A2
Used by Golgo 13 as his preferred weapon for sniper work, fitted with a telescopic scope. It is the most prominent weapon in the series. Also shown in the hands of American Coastguards members as an attempt to take out ship hijackers.
Colt M4A1
Used by Golgo 13 to eliminate Patrick Zalas at the end of "Sleep Inside the Prison".
FN FAL
A mercenary is armed with the FN FAL against the Savine brothers in the desert.
FN F2000
Used as the main assault rifle of the younger Savine sibling, an ex-French Foreign Legion soldier turned mercenary after the brothers were paid to kill Golgo 13. It was also portrayed during a rifle demonstration.
Heckler & Koch G36K
A mercenary is armed with a G36K against the Savine brothers in the desert.
Heckler & Koch XM29 OICW
Used by the older Savine brother, who also served in the French Foreign Legion with his younger brother prior to being a mercenary.
Ruger Mini-14
Shadow handles a Mini-14 with a scope and a long barrel. It's called the M14 in the show, which is impossible since the rifle is shown to have a curved magazine.
Steyr AUG
Inside a rifle case, it contains disassembled parts for a Steyr AUG assault rifle.
Unknown Custom AR15 carbine
Used by Golgo in his SWAT disguise to assassinate Jose Campos. Looks like the Patriot/M231, but having a very short barrel.
Sniper Rifles
Anschütz Target Rifle
Used by Golgo 13 to snipe Jake Quade after took an entire passenger jet full of hostages. The rifle is chambered in .22 LR in addition to seemingly having a different rifle buttstock.
Heckler & Koch PSG-1
A FBI Hostage Rescue Team (HRT) sniper is armed with the PSG-1 with a night vision scope.
Remington 700
Used by police SWAT snipers against Jake Quade in the 1st episode.
Riflecraft TMR1
Used by CO19 operators when the hijacked Air British flight lands in Heathrow Airport.
Tanner 6BR
Golgo uses one in "Muderous Crosspoint" when his client tells him to assassinate his target from a private plane in the air.
Machine Guns
Browning M2
A Military policeman fires the M2 from a chopper at Duke's Humvee over the Amazon. Duke uses the M2 as one of the weapons used to take down Garimpeiro's men, later destroyed to hide his tracks in Brazil.
Rocket Launchers
AT4
Duke uses an AT4 against Garimpeiro's men, destroying their truck. He bought it when he disguised as a Brazilian military official. A SWAT officer uses one to attack the hijacked van. Seriously?
FIM-92 Stinger
Duke uses two Stinger MANPADs in Brazil against corrupt Military police officers, shooting down their choppers after purchasing them under the guise of a Brazilian military official.
Grenades
M67
A hijacker in an Air British flight uses this as a weapon to get the passengers to cooperate.