The C8A1 is also the standard firearm of the Royal Netherlands Air Force and other specialist users within the Dutch and British militaries.

The carrying handle and rear sight assembly on top of the Diemaco C7 receiver features the most noticeable external difference between American M16A2s and C7s.

Diemaco C7s use a modified pre-M16A2 style two aperture L-type flip rear and front post iron sight line featuring two combat settings.

An approximately 0.070 in (1.8 mm) diameter aperture rear sight is used for normal firing situations for target distances up to 400 m (440 yd).

A second larger approximately 0.200 in (5.1 mm) diameter aperture battle sight is used as a ghost ring for short range quick target engagement and during limited visibility.

[3][4] The wing guards protected front sight was changed to a slimmer tapered round post of approximately 0.050 in (1.3 mm) diameter.

The optical sight was designed for the C9 light machine gun and includes horizontal and vertical mil-bars used for range determination and deflection, and a tritium glow-in-the-dark aiming post rather than the traditional crosshairs.

The 3.4× is powerful enough to properly see targets at the maximum accurate range of 550 m (600 yd), though like most magnified optical sights it is prone to criticism for creating tunnel vision in close quarters situations.

The result, the C7A2, has a four-point telescoping stock unit similar to that of the C8 carbine and a three-rail TRIAD that is clamped on the front sight base to allow accessories to be attached.

The addition of the TRIAD rail mount has made it easier for soldiers to attach accessories such as laser designator and tactical lights.

This version will require the use of the Colt Canada M203A1 with a different mounting system due to the new aluminium quad-rail handguard.

Since Colt Canada developed and released the MRR (Modular Rail Rifle) that uses a monolithic upper receiver with the Magpul M-LOK attachment system, the Canadian Armed Forces (CAF) might be heading in that direction instead, along with a shorter, 18.6-inch (470 mm) barrel, instead of the standard 20-inch (508 mm) barrel, and straight gas tube with a low-profile gas block[13] The possibility of using integrated suppressors is also something that is being looked into.

The Special Forces Weapon (SFW) features a longer, 410-millimetre (16.1 in) barrel of a significantly heavier profile than the C8A1 and a Rail Adapter System (RAS) handguard.

[4] The C8SFW is in service with the Norwegian Special Operations Forces as their standard rifle, as the more recently introduced HK416 does not feature a "heavy profile barrel" as the C8SFW.

The C8FTHB was quickly replaced by the C8A3, which features the same 400 mm (15.7 in) cold-hammer forged barrel and flat-top upper receiver as the C8FTHB as well as all the mid-life upgrades that appeared on the C7A2 such as the green furniture, ambidextrous charging-handle latch, magazine release and selector lever.

The C8CQB is similar to the American Mark 18 Mod 0 CQBR, having a 254-millimetre (10.0 in) or 295-millimetre (11.6 in) heavy barrel and a Vortex Flash Hider made by Smith Enterprise Inc.[15] The smaller Personal Defense Weapon (PDW) variant has an overall length of 530 mm (20.7 in) with its stock fully retracted.

A new bipod attaches to the same barrel yoke as the carrying handle and front grip, so current LSWs are made with a bayonet lug.

Unlike many M16 variants, it fires from an open bolt, necessitating the removal of the forward assist for operating safety.

[18] Custom tactical features: Diemaco offered a training version of the C7 named the C10, which would be a semi-automatic variant chambered in .22 Long Rifle ammunition.

In 2008 or 2009, Colt Canada introduced a completely new designed upper receiver with integrated rail attachment system.

[19][20] In 2010, the C8 IUR (Integrated Upper Receiver) was introduced as an upgrade by all four branches of the Danish military and the Danish Security and Intelligence Service's SWAT teams, as the "Gevær M/10",[21] In 2011, the Royal Canadian Mounted Police adopted a semi-automatic only version of the C8 IUR with ancillary components as their patrol carbine.

The C7A1 was first issued to field units of Logcoy/Danbn/Dancon of the Danish International Brigade, in October–November 1995 shortly before the transition from UNPROFOR to IFOR in Bosnia.

On 4 January 2009, the Danish Army lost a number of weapons including M/95 and M/96 rifles to armed robbers who overpowered the guards at Antvorskov Barracks.

[31] It features a 401 mm (15.8 in) free floating barrel, fully ambidextrous controls, flip up iron sights, a collapsible buttstock with more positions, and the Integrated Upper Receiver (IUR).

[34] The M/10 has gone through multiple changes since its original introduction in the Danish Army, including an extension of the rail and removal of the built-in iron sights in favor of Magpul MBUS Picatinny mounted back-up sights,[35] buttstock changed to Magpul CTR stocks, and an olive drab finish instead of the old black[36][37] and is issued with ELCAN Spectre DR 1-4× optics.

The Royal Netherlands Navy ordered only weapons fitted with magnifying sighting systems to fulfil its 500 m (550 yd) effective range requirement.

Many weapons are fitted with the L17A1 underslung 40 mm grenade launcher (UGL), the UK designation for the Heckler & Koch AG-C/EGLM.

[51][52] In July 2013, the British Ministry of Defence contracted Colt Canada for a £2.8 million mid-life upgrade of the L119A1 carbines used by the United Kingdom Special Forces.

Both L119A2 variants feature a custom integrated upper receiver (IUR) with rails that hold zero all around, a lighter profile barrel, straight gas tubes, Geissele trigger, SureFire 4-prong flash hider, a tan coloured Magpul 6 position collapsible CRT buttstock, Ergo pistol grip, and ambidextrous controls.

The Botswana Defence Force uses the MRR15.7M and MRR11.6S Modular Rail Rifle as patrol and Close Quarter Battle carbines.