M-16s of the Great White North: Diemaco & Colt Canada
Canadian troops have served side-by-side with Americans on the front-lines in the Global War on Terror since the beginning. And although their rifles look similar to U.S.-issue guns, 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 7.62x51mm 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"-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