You couldn't pay people to be that ignorant.
Jamming in VN was due to a combination of the gas system's inherent features, morons at Army Ordnance deciding to insist the ammo be loaded with entirely the wrong kind of (very dirty-burning) powder in a 'cost-saving' move, and a wholly-baseless belief - not coordinated with the morons screwing up the ammo - that the M16 didn't need to be cleaned and hence needed no cleaning kits (the M14's cleaning rods, made for a 7.62mm bore, would of course not fit in the M16's smaller 5.56mm bore).
The prime cause, the foul ammo, has been gone from the system for 40 years. XM193 Ball for the M16/M16A1 has been issued since then, and along with basic user maintenance and detail improvements to the weapon in the A1 version, totally addressed the problem. Coincident with the introduction of the M16A2 over 20 years ago, the standard ammo became XM855 Ball, which is designed for the NATO SS109 bullet, requiring a faster spin for stable flight, and so the M16A2 barrel has a more aggressive or faster rifling pitch than earlier versions. The A2 (and M4 carbine, which was briefly referred to as the M16A4 before being adopted as a Carbine) will handle all military 5.56mm ammo and about any commercial .223 Remington loading you could physically fit into the magazine. The XM855 or any 'Green Tip' ammo should only be fired in an M16A2, M4 Carbine, or civilian rifle specifically designed to supply the aggressive rifling pitch necessary to spin the SS109 bullets. I have fired some Green Tip from a .223 Ruger M77, a tack-driver (for a light sport rifle) able to deliver one-hole groups at that range using XM193 Ball, and at 50m five bullets from the XM855 made a horizontal 4" spread in a nice even line 3" below the point of aim, and all of them went through the target sideways (for some odd reason of chance, the bullet points were all up and pointing toward the point of aim).
Jamming now is due to one of two things - bad magazines or dirt, and dirt is strictly an operator issue. You can't flop your ass down in the sand and dump your rifle beside you or under your crap, and then not carefully check it for grit and clean it out when you get back up. It is also much better to use a dry graphite or Teflon lubricant in desert or cold environments than any kind of liquid, the liquid lube is a sand magnet in hte desert, and in the cold it will quickly render the weapon inop due to vastly-increased viscosity in cold conditions which seriously interferes with movement of the lockwork and firing pin.
