Alot of the problem I recall was the Use of Ball powder. I think it took a bit to find the right powder. Well that was according to the Fat guy with the pointy head. Dr something.. arms expert
The original powder specified for the 55gr ball rounds functioned perfectly in the AR-15/M16. As a way to save money, the bean counters switched to a powder buffered with a calcium compound - when firing, each shot was like blowing chalk dust into the receiver and barrel. It had essentially the same effect on the rifle that the fine sand in Iraq is having on our rifles now.
You still have the dirty direct gas impengement system that has to be cleaned
When a modern M16/M4 malfunctions due to fouling, it's because of dirt and sand clogging the weapon, not carbon (which mostly gets blown out and replaced by a fresh layer with each shot, otherwise the gas tube and carrier key would rapidly be plugged). That is why the rifle mist be cleaned so often, especially in dusty/sandy environments. Tight clearances between moving parts are the issue, not the direct gas system. The direct gas system is actually responsible for the rifle's accuracy, and a dirty rifle that hits the enemy is better than a clean-running piston design that doesn't, which is why the AK isn't really working all that well for the muzzies.
Just like the XM8 would have.
Ah, the wondrous XM8, the piece of **** that
melted during full auto trials and had even more reliability issues than the first issued M16s. Another ****ty HK product that the HK marketing team would have you believe was designed by the gods specifically to outperform the M16/M4; but it never does in a meaningful way. Much like the dust test performed some time ago, that supposedly showed that piston designs are better than the M4 because they have less stoppages after tens of thousands of rounds fired. What the "replace the M16 NOW!" guys don't tell you in their reports is that stoppages don't happen like clockwork, they start piling up near the end of the test because of significant wear and tear on the rifles. It doesn't matter that the M4 had five times more failures than the HK416 if it was happening after the ten thousand round mark, because no solider is going to fire five thousand rounds without an opportunity to clean the rifle, let alone ten or twenty thousand. And inside what was effectively a sandblasting cabinet, as well. The XM8 trials are just like the dust test; while skewed to make the M4 look bad, if one looks at the facts they plainly show that there is no replacement for the M16 that makes enough of a difference in performance to matter at the time. The problems we're facing in the middle east are a problem of tactics, not a problem with the issued rifles/carbines. You want to replace something, replace the SAW, which really is the jam-o-matic in sandy conditions that the M16 is made out to be.
The one thing that has never been attempted to be fixed is the caliber.
No matter what its called, its still a .22 center fire which was designed for hunting small varmits with four legs.
The most common commercial .223 ammunition is loaded with lightweight, rapidly expanding bullets designed for killing small animals. FMJ and heavy OTM projectiles used in the military loadings, fired into vital organs, kills a man every bit as effectively as any other piece of metal impacting the body at three thousand feet per second, penetrating deep into the body cavity, turning sideways and fragmenting, ripping apart whatever organs it passes through. Bullet design > caliber. The difference between .223 and .308 is a few hundredths of an inch; when a projectile penetrates your vitals and fragments, shredding tissue and stopping your internal organs from functioning, you tend to be just as dead regardless of the diameter of the projectile. There are plenty of dead commies and muslims that will attest to that fact - and the Afgans referred to the reds' centerfire .22, 5.45x39mm, as "the poison bullet" for a reason. The rifle has been fixed and the caliber doesn't need fixing; most of the people who say it does are people who have much more experience shooting varmints with .223 than human beings (As much as I hate to use that term to describe commies and jihadis...).