The old Marines I'm speaking of are Vietnam veterans who were issued M-14s, then re-issued M-16s and didn't like the latter in the conditions they has to deal with. Many of those guys saw their brothers-in-arms killed because their rifles failed them under fire. Some of those same guys are the ones who said the AR is a good match rifle, just don't take it to war.
And those old soldiers would be correct, because of the extremely well-publicized things that the armed forces did with the first batches of M16s they issued to the troops. Here's a hint: if the rifle is designed to be used with ammo of a certain type and you change that ammo to something different, it will not work. Not rocket scien- well...actually, it is ballistics. So, yeah, I guess it is rocket science.
In any event, once the first problems were worked through, by pretty much all accounts the majority of problems cleared up. We can, of course, argue all day if it ever got to be reliable enough. I'm not military and never have been, but the basic gist I get from people who worked with the M16/M4 is that if you take care of it, it works fine. If you don't, it won't. Every soldier and Marine would like an utterly maintenance-free weapon, but they haven't invented one yet. And, natch, I know soldiers and Marines who love the weapon. I know soldiers and Marines who hate it.
Returning to our thread at hand...what matters most is what the weapon
you own is going to do, not what the weapons issued to our front line troops are doing. My M4gery? More accurate than I am. After the first hundred-or-so rounds it's been jamproof. And while I'm not dragging it through the mud and tossing muck in the ejection port, I'm also pretty casual about cleaning. I'm certainly not babying the thing.
Seems like a good go-to gun to me.
Mike