Differences Between Canadian C7 and US M16

    According to user “RebelRouser” on AR15.com, the Canadian C7 rifle is a markedly different from the standard M16 issued to US armed forces. While the C7 is built off of the Technical Data Package from Colt, the Canadians claim to have made over 150 changes improvements to the basic rifle prior to entering production.

    The most interesting nugget is the claim for barrel life. The Canadian design utilizes a proprietary steel that claims to increase barrel life 2-3 times over a chrome-lined 4150 barrel in US rifles. Further, the barrel has squeeze (reducing bore diameter over the length of the rifling) to increase accuracy.


    Hi Steve 
    I apologize for not answering sooner. I‘m afraid I have been avoiding the 
    alligators chewing on my ankles to take care of the ones feeding higher up. 
    To answer your questions as presented: 
    The effective range published does not have much to do with the barrel but 
    is an infantry doctrine distance to do with the whole system including the 
    man, sights, weapon ammunition and expected employment. So when you see 
    effective range, it is almost always a subjective assessment of the system 
    capability derived by the user instructor (CTC) and rifle requirements 
    office (DLR), usually before the weapon is even bought. In the case of the 
    C7 it included iron sights and was extended (I think) when the C79 sight and 
    the C7A1 came along. The reference to the rifles origins (M16A1E1) is in 
    reference to the sight option first chosen by the CF. The heavy front 
    profile, 1 turn in 7inch barrel is definitely M16A2. As is the cartridge 
    deflector, handguards and many other changes. 

    Now lets talk barrels: 
    The C7 barrel is not the same as any M16 barrel except for the exterior 
    profile which is M16A2. The Material is to a formula developed here in 
    Diemaco (under Gov‘t contract) so that the entire bore and chamber 
    configuration can be integrally formed in one operation on a rotary hammer 
    forge. This process produces a barrel that is much stronger than the US 
    M16A2 barrel. The bore dimensions were developed to fire C77 ammunition, 
    (Chamber, bullet lead, diameters) the bore has dimensional reduction as the 
    bullet moves forward (squeeze) to increase life and accuracy. The bore is 
    plated with harder chrome than the M16. This allows greater wear life (2 to 
    3 times M16) and lets us machine C9 barrels from the same barrel blank. The 
    SFW was recently tested and purchased by the UK special forces and won in 
    competition against the Swiss SIG series rifles and the H&K G36 rifle. This 
    barrel is now in use by the Special Forces in five countries and the US Navy 
    Seals have expressed interest in putting them in the M4 Carbines that they 
    We have just completed a C8 Carbine upgrade program for Canada which is a 
    new barrel with an improved chamber and stronger extractor spring assembly 
    and a weaker ejector spring. These are the same internal configuration as 
    our very successful SFW barrel. 

    The C7 rifle and C8 Carbine is made under license with a Tech Data Package 
    provided by Colt to the Canadian Gov‘t. Diemaco reviewed the design and 
    made about 150 changes to the drawing package before Canadian production. 
    These are to numerous to mention her but include things like materials and 
    processes as well as a different barrel configuration and manufacturing 

    The improved handguard we designed here after CWO John Ginn kept beating the 
    Colt version off the weapon on the parade square. You probably can‘t tell 
    from the outside but if the you take the handguard off, you will notice two 
    types. The improved version has two large ribs under the heat shield and 
    three interlocking ribs on either edge as well as different material. These 
    were introduced late in the program so they had to be interchangable and be 
    a good match with the old handguard. 

    Another change you may notice is the small diameter front sight post that we 
    developed when soldiers complained that the US large square one actually 
    obscured the target at ranges of 300 and greater. 

    I hope this helps you with the discussion and thank you for your interest in 
    the C7. 

    Ian Anderson 
    ILS Supervisor 
    Product Engineering Dept. 
    Diemaco a division of Heroux- Devtek 

    Please note: Any opinions expressed or implied in this email are personal 
    are not necessarily those of Heroux Devtek or Diemaco 

    Nathan S

    One of TFB’s resident Jarheads, Nathan now works within the firearms industry. A consecutive Marine rifle and pistol expert, he enjoys local 3-gun, NFA, gunsmithing, MSR’s, & high-speed gear. Nathan has traveled to over 30 countries working with US DoD & foreign MoDs.

    The above post is my opinion and does not reflect the views of any company or organization.