Words: Rich Norman



The below pic from The Sun newspaper, of the Colt Canada L119A2 in use with UKSF at Exercise Winchester Accord, was originally posted on the L119 Owners Club Facebook group in May 2016.

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Underneath are legacy screenshots from Colt Canada’s website, which were used at the time to cross-reference with the Winchester Accord pic, in order to better understand the parts composition of the L119A2.

Needless to say, additional information has come to light in the past few years.

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Colt Canada’s website has also been updated:

97EF8173-AE57-4C31-A7F6-C525149C8D74It’s been observed that there are two distinct variants of the L119A2.

They are popularly defined by their uppers, although the differences between the two concern the kit-out of the lower as well:

  1. “IUR” – partial RIS; available in 10” and 15.7” barrel lengths
  2. “Alternative IUR” – full RIS; 10” barrel length only

Monolithic Design

The L119A2 exhibits a monolithic upper, meaning that the rail and upper receiver are conjoined in one continuous unit. It is referred to as IUR – which means Integrated Upper Receiver.

In 2016, I pointed out that  LMT owns the patent on monolithic uppers and that they successfully prevented Mega Arms from marketing their own one-piece upper.

It later became apparent that Colt Canada had officially licensed the monolithic upper receiver design from LMT, as evidenced by the US Patent number shown on the partial RIS ‘Alternative IUR’ L119A2.

See the patent PDF here.


Common Features – “IUR” and “Alternative IUR”

The following basic package is thought to be shared by both the “IUR” and “Alternative IUR” versions of the L119A2:

  • Magpul CTR stock
  • Original Ergo grip (not Ergo 2)
  • Geissele trigger group
  • Colt Canada standard trigger guard
  • Colt Canada ambi selector group
  • Magpul RSA
  • 511 VTAC two point sling, or;
  • Magpul MS3
  • Various Colt Canada ancillaries including BUIS (both folding and fixed), QD sling swivel, sling mount and grenade adaptor attachment

“IUR” Features

  • 10″ and 15.7″ barrel lengths (not 10.5″ and 16″)
  • Surefire FH556-216a flash hider
  • Colt Canada ambi mag catch
  • Colt Canada ambi charging handle (often has extended ‘tactical’ latch cut down, or replaced entirely)
  • Magpul ASAP
  • Grenade lug tapped for barrel nut anti-rotation bolt
  • Plug removed from Original Ergo grip


“Alternative IUR” Features

  • 10″ barrel length only (not 10.5″)
  • Birdcage flash hider
  • Standard Colt Canada mag catch
  • Standard Colt Canada charging handle
  • Magpul ASAP-QD
  • Grenade lug not tapped for barrel nut anti-rotation bolt
  • Plus retained in Original Ergo grip


Upper Receiver Patent/Serial Number

The pic below shows a 2017 UKSF contract 10″ IUR, sold commercially by Colt Canada to their domestic market.

It is assumed that IURs delivered to UKSF since 2017 have exhibited the patent number.

Earlier IURs did not and instead have the lower receiver’s serial number displayed in this position – applied by UKSF armourers.

The style of engraving of upper serial numbers by UKSF armourers apparently varies, with this blog able to verify white laser engraving in what appears to be Arial font.

The serial format (taken from the lower receiver) is a concatenation of:

Year of production (2 digits) + production unit (5 digits) + country code (GB)



NATO Stock Number – NSN

The L119A2 exhibits a NATO Stock Number – or NSN – on the right hand side of the mag well:


In the above pic we can just about make out an NSN which exhibits this string:


Other pics confirm this number.

According to the table below, which was posted in the L119A2 Owners Group on Facebook, the string ending 98 corresponds with the 15.7” model.

However, at this date I would be inclined to use the 98 number on a replica lower for either length upper. This is because, so far, I have only seen lowers with NSN markings ending 98 – regardless of upper.

The 99 lower may well be out there, or the NSN could have been created and never used. Only time will tell.


Also note that 16” (as related above) is an approximation, not the defined length of the rifle length IUR’s barrel (which is 15.7″).

There is no documentary evidence that I know of which suggests a different length for the SBR version of the IUR, so this is always taken to be 10″.

Custom and Practice

Charging Handle

In the wild, some L119A2 charging handle latches have been swapped out for vanilla versions, because the extended latch catches on gear. Others have had the existing latches cut down and in one case, a BCM charging handle has been seen.

The following illustration was provided by Jay Taranis:


More articles relating to the L119A2:

  • GG&G AR15 vertical fore-grip in use here
  • Magpul QDM and ASAP QD in use here
  • 15.7″ L119A2 upper in use here
  • Surefire FA556SA Suppressor here
  • GG&G Aimpoint T1 mount in use here
  • Magpul MS3 sling in use here
  • Magpul ACS stock in use here
  • Colt Canada parts – as used on the L119A2 – here
  • Manta Very Low Profile Rail Covers as used on the L119A2 here
  • UKSF Newcastle raid pics part 1
  • UKSF Newcastle raid pics part 2
  • UKSF Nairobi Kenya incident L119A2 parts breakdown here
  • UKSF Belize ‘Jungle Set-up’ L119A2 parts breakdown here
  • Confirmation bias (and the HSP Thorntail offset light mount) here
  • UKSF Ecosystem: S&S Precision Sling Clip – Old Gen – here
  • Inforce WML-type lights in use here

Illustrative Pics






partial RIS



Note: August 2018

Since May 2016 when this article was originally published, I’ve done my best to keep it refreshed with L119A2 updates. I’ve learned about these through my own research and from people in the know (some of whom have legit contacts).

However, in its original format and with a raft of assumptions it was beginning to creak. So, in August 2018 I decided to restructure it.

New info and pics are added when available.


Big thanks to Jay Taranis for his help at every stage of this article’s evolution, and to Gaz_isg, E27R, HRW and perr_mike for their support and clarification.

Some other contributors need to remain anonymous, but I’m no less grateful to them for their intel and clarification.

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