The SIG-Sauer P226 is the preferred sidearm of Red Troop and is used throughout the series. It is frequently seen holstered whenever the team are wearing their counter terrorist gear, but is normally only used for undercover work. The presence of the P226 isn't surprising, since it is the current sidearm of the British Army where it is used under the L105A1 designation.
Beretta 92
In "Class of 1980" (Episode 3.3) one of the terrorists (San Shella), uses an original Beretta 92 for most of the episode. This particular gun features plain grip panels, and a stepped slide (it narrows in thickness just ahead of the chamber) indicating that it is one of the first 1000 or so pistols made before the design was changed to the familiar profile.
Beretta 92FS
A number of Beretta 92FS pistols are used by the Italian security guards at the embassy in "The Class of 1980" (Episode 3.3).
Bruni Automatic 8mm CAL (M1911 Blank firing gun)
In Episode 3.2, "Never Go Back", the leader of the Zimbabwean "Fire Brigade" carries a Bruni Automatic 8mm CAL pistol (which is a theatrical blank firing only replica gun). The character may carry a real M1911 in other shots, but in this particular shot, he is aiming it at a child actor, so the blocked barreled replica M1911 is used.
CZ 75 Automatic
In "Never Go Back" (Episode 3.2) several characters use a CZ 75 Automatic shown with a ported barrel.
CZ 75 "Pre-B"
Several of the Chechens in "Weapon of Choice" carry CZ 75 "Pre-B"s.
CZ 75B
The Spetsnaz officer Vasily (Peter Sullivan) carries CZ 75B in "Weapon of Choice" (Episode 3.4).
Glock 19
A Glock 19 is carried by the former British officer Alan (Jalaal Hartley) "Deadlier Than the Male" (Episode 3.1).
Makarov PM
One of the Chechens in the armed crowd uses a Makarov PM in "Weapon of Choice" (Episode 3.4).
SIG-Sauer P228
A SIG-Sauer P228 can briefly be seen being used by Hector Du Preez (Ian Duncan) in "Never Go Back" (Episode 3.2).
Several of the terrorists in "Deadlier than the Male" (Episode 3.1) carry Umarex GPDA blank firing pistols that stand in for Browning BDAs. They can be recognised as GPDAs by their slide markings, which are visible in some shots, and the shape of the safety catch.
Submachine Guns
Heckler & Koch MP5A3
The standard-issue weapons for the SAS unit Red Troop in the TV show are Heckler & Koch MP5A3 submachine guns, which are always seen with Surefire forends weaponlights as well as the SEF-style lower receiver. These weapons are typically used in Red Troop's domestic hostage rescue missions.
The other SAS unit, Blue Troop, also use identical weapons, as do many Metropolitan Police SO19 (now CO19) officers throughout the show.
Heckler & Koch MP5SFA3
In "Class of 1980", a number of characters can be seen using what appears to be a Heckler & Koch MP5SFA3, the semi automatic only version of the MP5 used by, among others, the British police.
Calico M960A
In Episode 3.2, "Never Go Back", Becca takes a Calico M960A from the stash of weapons and looks it over, though she winds up using a Steyr AUG on the mission.
IMI Mini Uzi
The Mini Uzi machine pistol appears in several episodes.
MAC-10
The Al Qaeda terrorists in Episode 3.3, "Class of 1980", use many MAC-10 machine pistols.
SA Vz.61 Skorpion
The Tibetan nationalists can be seen with Vz 61 Skorpion SA machine pistols including the British officer Alan in Episode 3.1, "Deadlier Than The Male".
Steyr TMP
The Al Qaeda terrorists in "Class of 1980" also use a couple Steyr TMP Submachine guns.
Assault Rifles
AK-74 (Mocked up)
A number of Mocked up AK-74s can be seen being used by the African militiamen in "Never Go Back" (Episode 3.2) and by Russian troops in "Weapon of Choice" (Episode 3.4). They appear to be chambered in 7.62x39mm rather than 5.45x39mm, so it is likely that these weapons are AKMs fitted with AK-74 furniture and a muzzle brake.
AKM
AKMs are a common weapon used by terrorists on the show.
AKMS
AKMS's are a common weapon used by terrorists on the show.
Colt AR-15 Sporter-1
The M16A1 carried by Dempsey (Miles Anderson) in "Never Go Back" (Episode 3.2) changes to a Colt AR-15 Sporter-1 for firing scenes, as noted by its slab sided receiver.
CAR-15s are used commonly by the SAS in the show, almost always fitted with a Cobray CM203 grenade launcher. The "Stowaway" pistol grip and the areas of black tape covering logos on the lower receiver suggest that this weapon is built from an Olympic Arms rifle, most likely a K3B.
Colt M16A1
M16A1s are commonly used by the SAS in the show, normally fitted with a Cobray CM203.
Colt Model 723
Sergeant Sean Smith (Derek Horne) can briefly be seen carrying what appears to be a Colt Model 723 during a run at the start of "Never Go Back" (Episode 3.2).
Heckler & Koch G3A3s are used by various characters in "Never Go Back" (Episode 3.2) with various accessories.
Heckler & Koch G3A4
Henno (Ross Kemp) uses a Heckler & Koch G3A4 as his main weapon in "Never Go Back" (Episode 3.2) fitted with a slimline handguard, PRR pressure switch and an Aimpoint type red dot sight (replaced with a British Kite CWS for night scenes).
Heckler & Koch G36C
One of the weapons in the arms stash in Episode 3.2, "Never Go Back" is a Heckler & Koch G36C which is briefly handled but never used.
Heckler & Koch HK33A3
Members of Blue troop can be seen using Heckler & Koch HK33A3s on a number of occasions.
In Episode 3.2, "Never Go Back", Becca and Dave both used Steyr AUG A1 rifles.
Steyr F88 Austeyr
During some scenes, the Steyr AUGs in "Never Go Back" (Episode 3.2) change to F88 Austeyrs, as noted by the bayonet lug on the barrel.
Zastava M70B1
Zastava M70B1s are used by both Russian forces and Chechen terrorists in "Weapon of Choice" (Episode 3.4).
Zastava M70AB2
Zastava M70AB2s are commonly used by terrorists, and have also been used by the Russian army and the SAS operating undercover.
Sniper Rifles
Accuracy International Arctic Warfare
Whenever Red Troop requires sniper support, the snipers are typically armed with Accuracy International Arctic Warfare rifles in 7.62x51mm NATO, with the majority of the main characters using one at one point or another. This rifle was used by the British army, under the designation of L118A1.
Unknown Accuracy International Variant
Dave (Louis Decosta Johnson) can be seen using an Accuracy International variant in "Weapon of Choice". It doesn't appear to be the Arctic Warfare variant used in the rest of the series, as it lacks the correct flash hider on the end of the barrel, and there are 4 holes visible in the front face of the barrel. It is possible that this is simply an Arctic Warfare with the flash hider removed, but it is not possible the tell as the weapon is heavily camouflage with scrim.
Unknown Heckler & Koch G3 Sniper Variant
A police SO19 sniper in "The Class of 1980" (Episode 3.3) can be seen using an unknown Heckler & Koch G3 based sniper rifle. The rifle which it most resembles is an Heckler & Koch G3SG/1, however it has several differences: the rifle has a conventional trigger pack (lacks the secondary setting trigger), a larger E&L cheek riser, an E&L adjustable stock extension, no iron sights and what appears to be a thicker and longer barrel without a flash hider. Due to the rarity of G3SG/1s, it is more likely that this rifle is a regular G3A3 which has had a number of modifications and after-market parts added. The same rifle can also be seen on the Season 4 page where the same rifle is carried by a US special forces sniper.
LAR Grizzly Big Boar
A large bore sniper rifle of some variety is inside the weapons crate given to Red Troop in "Never Go Back" (Episode 3.2), but it is never picked up and all that is visible of it is the front of the barrel and muzzle brake, which resembles the LAR Grizzly Big Boar.
Unknown Sniper Rifle 2
This rifle can briefly be seen being used by a Chechen insurgent in "Weapon of Choice" (Episode 3.4).
Machine Guns
FN Minimi
Red Troop is frequently seen using the FN Minimi for support during missions overseas. The Minimi carried by Ed (Liam Garrigan) in "Weapon of Choice" (Episode 3.4) appears to be fitted with a side folding stock, similar to the one found on Para FALs.
Browning M1919A4
Browning M1919A4s are used by the Chechen rebels in "Weapon of Choice" (Episode 3.4), and another can be seen mounted on the cupola of a Russian T72 tank, likely standing in for the NSV heavy machine gun normally fitted here.
FN MAG
Although the majority of MAG type weapons in the show are actually British L7s, in "Never Go Back" (Episode 3.2) Becca (Heather Peace) uses what appears to be an FN MAG. It is not an L7, as noted by the fact that it lacks the sight bracket on the left side of the receiver, or the holes drilled in the receiver visible to show that it was removed. Strangely it is fitted with the same straight ribbed carry handle that is seen on the L7. It is also fitted with what appears to be a dark wooden butt and the bracket under the receiver for mounting an ammunition box, so it is possible that this machine gun is built from several different weapons, or perhaps it is an L7 built by a different country, such as India.
L7A2 GPMG
Being the standard machine gun of the British Army, the L7A2 GPMG is used on multiple occasions by the SAS on the show. It is also occasionally used by terrorists on the show. It can be identified as the L7 by the sight mounting bracket at the rear of the left side of the receiver, and more specifically the A2 version by the ammunition box mounting bracket under the receiver (the only external difference between the A1 and A2 models). Every time a GPMG appears it seems to be the same weapon, with a yellow "9" painted on the butt. Numbering like this is a common feature of British Army weapons, so it appears that this is a genuine surplus weapon.
PKM
Pierre Du Preez (Adam Croasdell) uses a PKM to defend the farm in "Never go Back" (Episode 3.2).
RPD
An RPD can briefly be seen being used by a Russian soldier in "Weapon of Choice" (Episode 3.4) during the attempted rescue attempt at the start of the episode.
Shotguns
Armsel Protecta
Henno (Ross Kemp) uses an Armsel Protecta with a 7" barrel in Episode 3.2, "Never Go Back", where it is depicted as a multi-shot grenade launcher.
Double Barrel Shotgun
A full length Side by Side Shotgun is among the weapons carried by the Chechen rebels in "Weapon of Choice" (Episode 3.4).
Franchi SPAS-12
Dave (Louis Decosta Johnson) can be seen handling a Franchi SPAS-12 fitted with a barrel extension/choke adapter taken from the weapons crate in "Never Go Back" (Episode 3.2), although he does not take it on the mission.
Sawed Off Side be Side Shotgun
One of the Chechen rebels in "Weapon of Choice" (Episode 3.2) uses a sawed off shotgun to kill an informant.
Winchester Model 120 Ranger
A sawed off Winchester Model 120 Ranger is seen in season 3, episode 3, "Class of 1980" in the hands of terrorists. The Model 120 Ranger is a cheaper variant of the Model 1200, and can be identified by the vented rib above the barrel, and the "humped" shape of the trigger guard.
Heavy Weapons
Cobray CM203
Red Troop's M16s and CAR-15s are often fitted with what appear to be M203 grenade launchers. However, a close inspection of the receivers reveals that they are actually the look-a-like Cobray CM203 37mm launchers which are often used to substitute for the M203 in many films and TV shows.
LAW 80
Louis (Christopher Fox) can be seen carrying a LAW 80 when the SAS arrive at the airport in "Deadlier than the Male" (Episode 3.1).
RPG-7
RPG-7s can be seen throughout the series used by terrorists and opposing forces.
Unidentified Mortar
An unifentified mortar can be seen being used by African forces in "Never Go Back" (Episode 3.2).