Filthy 14 is a AR15 used as a carbine class loaner gun, for students who brought a firearm not up to putting out 1K rounds or more in a weekend. It's already past 50K rounds as of the last show display it was featured.
Lots of firearms are blowback - they work off the inertia of the bolt holding the cartridge in place long enough the bullet leaves the barrel. By then they have absorbed enough energy to start cycling. Most pistol rounds over 9mm, and most rifle calibers over .22, don't use it. The gas pressure at that threshold is usually enough to move the bolt open before it's low enough to safely expose the brass case in an unsupported position.
What's interesting is the public pays no attention to the fact a self loading action can and does extract the brass while there is still some residual barrel pressure left, and gas residue blows past the case into the action. ALL blowbacks do that, the HK roller lock bolt does it, and so do all piston and DI guns. When you find gas residue on the bolt lugs of a piston gun - even M1's do that - it's gas from the chamber.
Piston guns are not immaculately cleaner, moot point, gas residue doesn't jam the action. Mike Pannone ran a test, firing 2400 rounds + from a dry AR15 until it jammed, about 10 basic combat loads. Nobody in combat could shoot that much ammo, and not do some basic maintenance like add oil or wipe it down, over a period of at least seven days that it would take.
If your combat firearm is jamming from gas residue, no doubt you can keep up the fight until you are knee deep in grenade pins, too.
What causes weapons to malfunction is 1) a bad or damaged magazine, 2) dirty or damaged ammo. What caused the
18 Month difficulty with the issue M16 circa 1968 was a) repurposed powder that precipitated binder residue in the loading process, making some bad ammo, b) a sudden 400% increase in production, which allowed a number of subcontracted barrels with tight chambers to be fielded, c) budget cutters eliminated the chrome chamber spec that had existed since the Garand, d) an oversell that the M16 was maintenance free - something a draftee with no firearms experience would naively accept to get out of doing work, e) the weak magazine design, which added another 10 rounds and made the result a curved mag feeding a straight mag well.
We are still dealing with that last mistake - non tilt followers, teflon coated mags, polymer construction. If you can drop a loaded mag on the feed lips and render it unserviceable, as many have experienced, THAT's a weak link. Not the gun. It's relevant to note the M16 uses 8+ mags as a combat load, the AK is issued 3 - three - for the duration of the enlistment. Completely different logistic philosophy - and expectations of survivability.
There certainly were much fewer issues after 1970, but the damage to the gun's reputation was already done, and millions of non service experienced citizens with no firearms training think the gun has been flawed for decades. Not so much. I never had a malfunction in the 22 years I served in the Reserves - issued a GM Hydramatic, FN, or Colt, blanks or live fire.
One in one hundred citizens actually enlist and serve in the Army, meaning the other 99 haven't a clue what it's like in training or on duty. Nonetheless, it's America, the one country where you can know absolutely nothing about a subject, and believe your opinion is as good as the next man's.
