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M16s of the Great White North

The Canadian C7 and C8 families have features unique to the Canadian Forces.


Canadian involvement with the Colt M16 series of rifles began as a result of that country’s Small Arms Replacement Program (SARP), which sought to supplant the FN-FAL-based C1A1 rifles chambered in 7.62x51 mm NATO that had been in use by Canadian troops from 1955 to 1983. The winner of the program for the new Canadian battle rifle was the Colt M16A2.

After adoption in 1983, the Canadian government assigned Diemaco contracts to manufacture the guns for Canadian Forces, and the Colt Technical Data Package (TDP) was licensed to the Canadian government to build the rifles. The Canadian government also entered into a licensing agreement with Colt that prohibited sales that would compete with Colt in the United States. Originally a division of Magna Int’l, in Kitchener, Ontario, Canada, Diemaco was established in 1976 with a mandate to become the center of excellence in small arms for the Canadian Forces, by providing engineering and development of future small arms and, eventually, to manufacture the new Canadian C7 service rifle.

Although the C7 was based on the M16A2, the Canadian military did not accept it as originally designed by Colt. Our neighbors to the north required some major changes to make the rifle suitable for Canadian Forces. First, the three-round-burst system had to go, as the Canadian military believed ammunition conservation and effectiveness of automatic fire were training issues, not mechanical ones. The second major change was that the Canadians would not accept the U.S. Marine Corps-mandated fully adjustable rear sight, believing the original “A1”-style rear sight was less complicated and far more practical as a combat sight. Another change was the addition of a buttstock spacer.

Aside from those relatively minor modifications, which largely addressed the rifle’s functionality, the most significant change was to the barrel. It retained the M16A2 outside profile, but, inside, the chrome-lined bore, the rifling and chamber dimensions were not of standard Colt design. That was because Diemaco cold-hammer forged its barrels, a process used by Steyr, Heckler & Koch and Glock to name but a few. The barrel starts as a solid bar stock blank with a pilot hole drilled through the center. The blank is then placed in an Austrian GFM hammer forge. A mandrel is placed inside the pilot hole, and the machine exerts tons of pressure on the outside surface in a rapid multi-hammering process drawing the barrel blank out roughly one-and-a-half times its original length and cold-forging the blank around a mandrel, which forms the chamber, leade and rifling.

Along with the C7 family of rifles came the C8 family of carbines, which retained the early 14.5-inch-long lightweight profile, “pencil” barrel. The C8 was equipped with a two-position telescopic polymer stock. Another modification of the C7 utilized a flat-top upper receiver—one the Canadians referred to as having a “Weaver profile.” It predated the adoption of the MIL-STD-1913 rail of the M4 and is not compatible. The new rifle with the flat-top upper receiver was designated C7A1 and, correspondingly, the carbine was designated C8A1. Existing guns could be converted by replacing only the upper receiver while retaining the original barrel. That made a full-scale changeover quick and inexpensive.

Canada was also one of the first nations to adopt an optical sight for every soldier. Most countries at that time, including the United States, issued optics only to snipers or designated marksmen. Canada adopted the indigenously manufactured ELCAN C79 optical sight to top the upper receiver. It gave all soldiers the ability to identify and engage targets at longer ranges because of its 3.4X magnification.

The Canadian Forces eventually required a mid-life upgrade to their C7s and C8s. Pleased with the rifles’ performance and seeing no need to replace them, they wanted to update the designs to address feedback received from the end users in the field. The first change was the replacement of the fixed stock with a telescoping unit, allowing the rifle to be slightly more compact and easier to use with body armor, tactical vests, winter clothing and load-bearing equipment. One of the mandatory requirements was to keep the 20-inch barrel to maintain accuracy and the optimal lethality with service ammunition. Another call was to make the guns ambidextrous, so the Canadian government obtained a license to manufacture the Norgon ambidextrous magazine release in Canada. New ambidextrous selector levers were also installed on the upgraded guns, as well as modified ambidextrous charging-handle release latches. To allow the mounting of light sources and lasers, a Triad rail adapter was added to the front of the rifle on the front sight base, providing mounting positions at 3, 6 and 9 o’clock. Green furniture (handguards, pistol grip and stock) was added to reduce the rifles’ contrast when placed in front of the camouflaged Canadian Pattern (CAD PAT) uniform.

Diemaco entered into the international market with sales to the Netherlands, Denmark, the United Kingdom and Norway. But perhaps the most notable achievement was a special order of modified C8 carbines for Great Britain’s renowned Special Air Services (SAS) Regiment. The SAS spent more money on the testing of new arms than it did for the actual procurement. To meet the SAS’s requirements, Diemaco customized the barrel’s length and profile. The unit’s accuracy requirement could not be met with a 14.5-inch barrel, so the length was extended to 15.7 inches. Due to an extended firing requirement a heavy profile barrel was also developed. A 40 mm LV grenade launcher was to be mounted onto the front sight forging, so a new front sight base was designed to increase that component’s strength. The new design was dubbed the Special Forces Weapon (SFW), and this would go on to be the firm’s crown jewel.


Although never put into production, another M16 variant—the C10 training rifle—was way ahead of its time. The design fired inexpensive .22 Long Rifle cartridges and gave troops the ability to train in indoor ranges that would not allow the use of 5.56x45 mm NATO. The C10’s one-piece polymer lower receiver and buttstock matched the weight and feel of the standard C7 rifle. Diemaco has also made various special-purpose iterations, including the C7CT and C8CT, which are designed to serve as short-range sniper rifles as well as designated marksman rifles.

The Canadian firm also worked with Colt on the development of a more powerful military arm. It was Colt’s Henry Tatro who designed the original Colt Light Machine Gun (LMG) to be a light support weapon (LSW) for sustained, suppressive fire. The LMG incorporates an extra heavy barrel, fully adjustable rear sights and an open-bolt mechanism. The hammer functioned as the bolt carrier release, as well as striking the firing pin. When the trigger is pulled, the connector lowers the hammer out of engagement with the bolt carrier, releasing it forward. At that point the hammer is held by the automatic sear. Once the bolt carrier tripped the sear, the hammer would release to strike the firing pin. Due to lack of funding and an ongoing strike, Colt was unable to complete development, but a team from Diemaco decided it could finish the project and get it to market. Because of its engineering expertise and the firm’s small size, Diemaco was ideal for the job, calling the gun the LSW. The open-bolt mechanism was modified along with many other features. Complete guns were manufactured in Canada, and 30 went to West Hartford, Conn. There Colt changed the lowers out for U.S. lowers prior to sending them on to the U.S. Marine Corps.

Diemaco had manufactured many component parts for Colt Defense through the years, and the two firms worked on joint projects such as the open-bolt LMG, so both companies knew what they were getting into when on June 3, 2005, Colt Defense announced the acquisition of Diemaco. The new company was called Colt Canada. The move enabled Colt Defense to take full advantage of the excellent resources the Canadian firm had to offer, including a professional and well-equipped R&D department with specific expertise in the M16 system.

It was Colt Canada/Diemaco that would sell the LMG to military customers. The Danes and the Dutch were fond of the design but not of the open-bolt mechanism. Both nations wanted a closed bolt, so that is what they got. All of those contract guns were made with closed-bolt operation. Colt Defense ceased sales of the LMG in 2009, but the LSW is still in production by Colt Canada.

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4 Responses to M16s of the Great White North

J Harlan wrote:
March 12, 2013

The Galil won the first trial to replace the FN C1 but the Israelis wouldn't allow the rifle to be manufactured in Canada. The M16 won the subsequent trial versus the FNC. Building in Canada resulted in a good rifle bought at very high prices > $2,500.00 each when an over the counter Colt HBar cost ~ $ 750.00.

Cj wrote:
March 06, 2013

Having used the C7 for years as a member of the CF I would agree that it was superior to the general issue US M 16. The Elcan scope was unreliable, fogging in winter and dismal in CQB. Members of the CF who were not combat arms had extreme difficulty zeroing the rifle, due to lack of training and familiarity. perhaps the standard sights would have been better for non-combat arms. It had 'back up sights on top of the optics which were ineffective. The adaptability was a plus, being able to change to a different sight, but the CF lacked the budget to make this a reality when I served. A gas piston would have been a significant improvement.

redboner wrote:
February 25, 2013

The hammer forged barrels were required because Colts standard barrels would not maintain accuracy over the life of the firearm. In testing, according to my sources, some barrels lost accuracy at less than 1,000 rounds.

rubicon762 wrote:
February 23, 2013

Sounds like Canada is ahead of the USA in some ways, in adapting the AR-15/M16 design to there needs: 1)Mandating a 20" barrel so that the bullet reaches it's designd velocity. 2)Green funiture is superior. Any color but target indicator Black! Our troops in Iraq/Afganistan quickly painted there rifles to match terain. 3) Canada was YEARS ahead of every other nation in using optics on all there rifles. Maybe we American's should pay more attention to our neihbors to the north.