The barrel length is a big problem, and I cannot (for the life of me) fathom what the advantage to a short barrel on a rifle is.
The powder in a rifle round burns too slowly; as the barrel length is reduced, more powder is left unburnt by the time the bullet exits the muzzle, which means two things: reduced velocity and huge muzzle flashes.
This can be ameliorated by using a faster-burning powder (like a pistol powder), but if any of the short-barrel ammo finds its way into a rifle or SAW, those weapons will be blown apart by the absurd pressures developed from too-rapidly burning powder.
What the M4 suffers from, IMO, is the desire by the DOD pencil pushers for one weapon that will do everything. I’m not an expert in combat arms, but I’ve never heard of “one weapon that does everything.” Our guys need a sub-gun for urban close-quarters stuff now, and they’re trying to cut a rifle down to do the job. Why not just re-issue the Thompson 1927’s we have in stock? They spit out .45 ACP’s at a nice clip, which put enemies on the ground in a hurry. If they don’t want to do that then why not find some other sub-gun in 9mm or .45ACP to do the job? Why try to cut a rifle down to a pistol size and still pretend it is a rifle?
Makes no sense to me.
Ever had to get out of a burning vehicle in a hurry?
1. The SCAR was given a lubrication change after the testing started that was not provided for the M4, or any of the other weapons. It should have been eliminated from the testing.
2. The dust was extreme and in almost any case would not be encountered in the 'real world'.
3. As soon as defects in any of the weapons tested occurred, they were repaired or corrected, except for the M4's. This in itself negates the entire test regimen and should have been repeated/restarted.
4. There is no specificity for any of the failures and as to type.
5. No consistency in the human factor or is it addressed.
6. Inclusion of two different testings for the M4 or if the same weapons were tested in BOTH regimens. This would lead to far more M4 failures due to end-of-life issues.
7. Lastly, this testing is a limitation type of test, and does not provide any 'real-world' comparison.
The 14-inch barrel is the most efficient for the 5.56 and the twist needed for the M855 or the new M262(77gr). The basic load-out for each soldier is close to 65 lbs+, with body armor, helmet, radio, ammo, pack, water, etc, weight is a significant factor. CQB also depends on a fast handling shorter rifle as circumstances change in an urban environment from long-range(300meter average) to CQB(house-clearing).
Why not just re-issue the Thompson 1927’s we have in stock?
This has been stricken from issue since the 50's, even though some were used in Nam, they are complex and difficult to maintain, do not offer improved performance and has limit usability at ranges now being engaged.
The 1903 Springfield, which you mentioned in another post, was issued in some form all the way into VN, and some even as far as Grenada in 1903A4 form. It too went through a number of developments from ammunition to manufacturability in it's lifetime was the primary issue in the Burma campaign, carried in Europe and in the intial landings at Guadalcanal by the Marines. It lasted in inventory well over 40 years in some form. The M14 is still carried by SpecOps groups such as the SEALS, and even in some forms in Iraq(modular AR type stocks, sniper variants). It has not 'gone away' and is still one of the issue weapons on the react teams for US Navy vessels.
The M16/M4 is the first commercially made rifle that the military has bought into. The M14 being the last internally developed system. The politics of the 'big-bore' club tried to doom the rifle from the begining. Over it's lifetime, and with understanding of it's limitations, the system has developed into a complete battle-rifle. It lacked the longer range ballistics because from it's inception it was designed to fight in the 100-200 meter range, lessons learned from Korea and Nam. However, Desert Storm and a few brushfires showed that ranges in 'real life' were from 200-400 meters and improvements in ammo led to the M855(issue), differing barrel twists, and improvements in optics. It's simplicity in design and function, with fewer parts to break, easier maintenance, and parts interchangability make it a superior issue rifle.
Would I like to see it in the HK416 form or a gas/piston system? Of course. However the gas systems also have problems related to exhaust of the excess gas. They kick up dust in front of the shooter and limit visibility. The system has to be 'tuned' to the ammunition it fires for reliability. Any change in bullet weight and powder make it finicky at best, totally unreliable at worst.