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

have.

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.



Differences:

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

processes.



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