Well I just ordered a C8 Green furniture Canadian Colt today.
Now I need to find an old school Eotech and a tri-rail...
To the guys that deployed with C8's can you post pictures of what it should look like ? I found this on google image..
Found Some good info on the C8 Barrel,
Now I need to find an old school Eotech and a tri-rail...

To the guys that deployed with C8's can you post pictures of what it should look like ? I found this on google image..


Found Some good info on the C8 Barrel,
The 20 makes 3100 fps or 946 m/s with 62 gr. The 15.7 makes 2900 or 890 with the same ammo.
The 20 has a "government profile" light under the hand guards barrel.
The 15.7 has a heavy sleeved barrel, about the same size as the M4 SOCOM barrel.
They both weigh close to 3kg. (20 - 3.31 kg and 15.7 - 2.97 kg)
The carbine is typically more accurate than the rifle because of the heavy barrel out to about 300 m. Beyond that the rifle's velocity has an advantage with wind and stability.
The carbine will also make better hot groups because of the extra thermal mass and the more rigid barrel.
This is also just not true, there are very definitive and measurable results between the two. Nor is it that true that we don't know how to measure barrels.
Small arms barrels have a number of different nodes of vibration. These vibrations cause the muzzle to move. If you shorten a barrel 1 mm at a time and graph the accuracy, results vary in a pattern of larger and smaller groups. The smaller group sizes along that graph are the accuracy nodes.
When you combine the accuracy nodes, with customer requirements, functional requirements such as dwell time and terminal requirements such as stability and velocity, you get what we found to be the ideal carbine length - 15.7 inches.
This is not an inexpensive test to conduct, as you might imagine. This required firing thousands of rounds in a number of samples to be statistically relevant. Further, the C8 has a choke hammer forged into it to improve accuracy and barrel wear. That means this was not a hack saw test, but that each set of test barrels needed to be hammer forged specifically for a pre-determined length.
15.7 inches (as measured from the breech face to the muzzle) is one of the accuracy nodes. 16" is not an accuracy node (though it may be for some steel and some profile), it is an arbitrary legal requirement in the US just as the Canadian 18" length restriction has nothing to do with accuracy or function. With the flash hider, the barrel is just slightly over 17". I suspect the M203A1 sleeve also enhances accuracy just as barrel tuning weights have an effect on group size.
These rifles are not permitted to be sold to the US, nor is it legal to export them because of US export and import laws and our licence agreement with the US state depts. The lengths have nothing to do with US laws. The barrel length was determined exclusively based on performance for a military customer requirement.
Cheers,
Matt
This is not true in the slightest. We have fired tens of thousands of rounds without any issues. It does not increase wear anywhere or decrease reliability in the slightest. The bolt carrier is not weakened and the carrier does not contain high pressure anyway. We have provided thousands of rifles for LE customers with the exact same bolt with no issues - even with .223 vs 5.56 which has much more effect on carrier velocity deltas than any carrier modification.
The design that was chosen removes less than a quarter inch of steel were the auto sear would contact. The semi carrier is the very early Colt AR15 version. Our instrumentation can't even measure the difference in carrier velocity between the two types. In addition, the heavy buffer adds more mass than has been removed from the carrier.
Our reliability is guaranteed based on tens of thousand of rounds fired in statistically significant samples of this semi carrier compared with hundreds of thousands of rounds fired through automatic carriers.
It is an internet myth that a semi carrier has any effect on reliability.
It's a bit more drawn out and complicated than that. Colt Canada supplies several NATO countries.
The C8 SFW started out as a prototype for UK SF and became known as the SFW after four more NATO country's SF adopted it. There were two sleeves: one for simon grenades and one for a particular brand of suppressor. The original SFW also used a heavy solid forged gas block/front sight forging.
Many of these were sold with KAC RAS.
The C8 was a pencil barrel with C7 style carry handle upper. It was made on a standard mandrel for the hammer forge.
The SFW used a proprietary improved chamber design that required a new carbine mandrel, a longer barrel for improved velocity and a heavy barrel for increased rigidity and more thermal mass. All carbines use this chamber now. The barrels were tested at different lengths for maximum accuracy nodes, hence the 15.7 length.
The C8A2 was a heavy barrel 14.5 in carbine with a weaver upper for the Dutch and was often called the Dutch barrel. The majority of early police sales used C8A2 with 1913 uppers.
Canada adopted a flat top before the US adopted 1913. The weaver was more accurate and consistent. The new NATO rail standard uses some weaver features.
The CF adopted the new improved chamber for C8's but did not designate a new weapon. There was a small 2 roll marked on the barrel to indicate improved carbine chamber - but they kept the pencil barrel.
The C8A1 was a pencil barrel with a flat top upper.
The CF then adopted a small QTY of C8FTHB for urgent operational requirements which was essentially an SFW - but with weaver upper, and a M203A1 sleeve. There were also a few upper kits. These were ones that may have been painted.
The sleeve is required to be milled from pre-hardened steel to be able to handle the loads required. This makes it quite expensive and hard to machine - particularly in small QTY.
Later, after the C7A2 mid-life program was running, to consolidate the fleet, the CF adopted the C8A3 - essentially a C8FTHB with ambi controls to match the C7A2, Canadian average green furniture, etc.
The reason that these were so successful is that Diemaco was a full MILSPEC facility, NATO AQAP certified, contained a full test and evaluation centre and was willing to do R&D and produce short run, specialized products and test and certify them to the NATO standard. Canadian MILSPECS often exceed US or NATO specs - for example Cold testing. US MILSPEC is for 36 below, Colt Canada tests to 65 below. To make a rifle suitable for arctic ops, the chrome was upgraded to a thicker, more ductile hard chrome that performs well in extreme high and extreme low temperatures.
These barrels outperformed all competitors in the UK trials and in fact were the only rifles that did not need to be re-barrelled. Some trial guns were used operationally after the tests were concluded. To put it in perspective, the testing cost more that the contract was worth.
As a comparison Colt's produces about 650 rifles a day which would be a month's production for Colt Canada. The barrel steel for the Colt Canada cold rotary hammer forged barrels is the best in the world. The steel un-drilled blank costs more that a completed chromed M4 barrel. Each barrel, bolt and extension are MPI and marked with a batch number for tracking as extensive destructive testing is done on every batch. Every barrel is air gauged twice, scoped twice and every one is test fired.
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