I shared the M4 heavy barrel thread with a friend in the military. His first response was:
The fitting of a heavier barrel is a good idea, but the switch to a hammer forged barrel – which conveniently they can easily obtain from their new Colt Canada subsidiary (which come moronic ####### in Ottawa allowed to be sold out of Canadian hands). The next thing they need to do is replace the direct gas impingement system with an adjustable short-stroke gas piston. Then you can do away with that stupid three-shot burst and instead, train your soldiers to exercise fire discipline like every other army in the world does.
Then he wrote:
and I forgot the most important one – lose that crap SS109 ammunition and switch to a heavier weight bullet..
I wrote back and said I did not see the connection of a gas piston to 3-shot bursts.
He answered:
The two (direct gas impingement and 3-shot bursts) are not connected, they are both just bad ideas that should be consigned to the junk heap. Direct gas impingement introduces hot dirty das into the receiver – and with all due respect to Eugene Stoner - in my view never a great idea. It is also not adjustable. I prefer a short-stroke gas piston which can be adjusted to take into account differences in gas port pressure. The three-round burst setting is a solution to the problem of badly trained troops with poor fire discipline. I say leave the full-auto capability and train you soldiers not to ‘spray and pray‘. Interestingly enough, while they appear superficially similar, the hammer forged barrels of the Canadian weapons have twice the life of the US-made M4 barrels (10,000 round versus 5,000). Doesn’t take the brains of an Archbishop to see where this is an advantage.
The SS109 ammunition was designed originally to provide optimum performance in the 20 inch barrel of the M16A1 (and of course to penetrate body armour and helmets worn by Soviet troops). Shortening the barrel to the 14.5 inches of the M4 reduced muzzle velocity by a degree sufficient to drastically alter the terminal performance. The performance was always marginal, and reducing the velocity by approximately 300 fps (and thus energy) does it no favours. The terminal performance of the 5.56 mm ammunition was always dependent upon the round tumbling inside the body, creating a larger wound cavity. The SS109 projectile begins to tumble after approximately 14 inches inside the human body, but unfortunately the current enemy is typified as an ‘undernourished Asian male” who does not wear helmets and body armour and whose body generally is 12 or less inches thick, and you can see the problem. So we have a round of ammunition that, being slower, has less energy to begin with, and is unable to fully transfer that energy to the target because it does not tumble as it was designed to do but rather exits the body leaving a small .22 calibre through-and-through wound. Add in the fact that the round has armour-defeating capabilities which are completely useless in the current operational theatre, and you can see why it is less than successful.
A heavier projectile will begin with more energy – and having more to transfer will provide better terminal performance. Hence the popularity of the 77 grain Mk 262 Mod 0 and Mod 1 ammunition over the current 62 grain M855/SS109 ammunition. The Mk 262 ammunition has more energy at 300 metres, than the SS109 has at the muzzle. It also tumbles earlier in the body.
The fitting of a heavier barrel is a good idea, but the switch to a hammer forged barrel – which conveniently they can easily obtain from their new Colt Canada subsidiary (which come moronic ####### in Ottawa allowed to be sold out of Canadian hands). The next thing they need to do is replace the direct gas impingement system with an adjustable short-stroke gas piston. Then you can do away with that stupid three-shot burst and instead, train your soldiers to exercise fire discipline like every other army in the world does.
Then he wrote:
and I forgot the most important one – lose that crap SS109 ammunition and switch to a heavier weight bullet..
I wrote back and said I did not see the connection of a gas piston to 3-shot bursts.
He answered:
The two (direct gas impingement and 3-shot bursts) are not connected, they are both just bad ideas that should be consigned to the junk heap. Direct gas impingement introduces hot dirty das into the receiver – and with all due respect to Eugene Stoner - in my view never a great idea. It is also not adjustable. I prefer a short-stroke gas piston which can be adjusted to take into account differences in gas port pressure. The three-round burst setting is a solution to the problem of badly trained troops with poor fire discipline. I say leave the full-auto capability and train you soldiers not to ‘spray and pray‘. Interestingly enough, while they appear superficially similar, the hammer forged barrels of the Canadian weapons have twice the life of the US-made M4 barrels (10,000 round versus 5,000). Doesn’t take the brains of an Archbishop to see where this is an advantage.
The SS109 ammunition was designed originally to provide optimum performance in the 20 inch barrel of the M16A1 (and of course to penetrate body armour and helmets worn by Soviet troops). Shortening the barrel to the 14.5 inches of the M4 reduced muzzle velocity by a degree sufficient to drastically alter the terminal performance. The performance was always marginal, and reducing the velocity by approximately 300 fps (and thus energy) does it no favours. The terminal performance of the 5.56 mm ammunition was always dependent upon the round tumbling inside the body, creating a larger wound cavity. The SS109 projectile begins to tumble after approximately 14 inches inside the human body, but unfortunately the current enemy is typified as an ‘undernourished Asian male” who does not wear helmets and body armour and whose body generally is 12 or less inches thick, and you can see the problem. So we have a round of ammunition that, being slower, has less energy to begin with, and is unable to fully transfer that energy to the target because it does not tumble as it was designed to do but rather exits the body leaving a small .22 calibre through-and-through wound. Add in the fact that the round has armour-defeating capabilities which are completely useless in the current operational theatre, and you can see why it is less than successful.
A heavier projectile will begin with more energy – and having more to transfer will provide better terminal performance. Hence the popularity of the 77 grain Mk 262 Mod 0 and Mod 1 ammunition over the current 62 grain M855/SS109 ammunition. The Mk 262 ammunition has more energy at 300 metres, than the SS109 has at the muzzle. It also tumbles earlier in the body.
