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Sunday, June 27, 2010

The Fighting AR15, Part 1- Gas Piston vs Direct Impingement

The Fighting AR15, Part 1- Gas Piston vs Direct Impingement

There is a lot of discussion about the reliability, or lack there of, of the AR15 platform. The latest and greatest solution to this fabled lack of reliability is the gas piston.

Well, I don't buy into it.

Before I explain, a story........

I had gone to the VA Hospital in New Orleans to get a check-up and decided that since I was in the city I would visit a local store that specializes in tactical weapons and supplies. The owner is a Former Marine Gunsmith and has a great wealth of experience and knowledge. I had never done buisness with him, but had friends that had.

At the time I was building a new AR15 Carbine and was looking for a complete upper. I didn't want anything special other than a flat top and M4 barrel profile. When I approached the counter I introduced myself and we exchanged war stories and credentials for a few minutes. Then I asked if he had any AR uppers in stock. He said he had only one left. It was a LWRC or POF or some other crazy gas piston $2000 upper that weighed and cost far more than it needed to to do the job. I told the store owner that I thought the gas piston was a fad for the inexperienced gun guy that bought in to all the “My brother's best friend is a super secret CIA SEAL Force Recon Parajumping Ranger with the NSA and he said the AR15 gas system sucks” crap.

I was quickly put in line by an older man to my right. You know the type, the gun-shop hangout guy that knows all and offers all his advise unsolicited. He began to explain to me that the reason why “the gooks kicked our ass in the Nam was because we had M16s that did not work and they had Aks”. He then told me that with that upper there I could fire 2000 round in one day with no malfunction. He swore be damned that that upper was the end all be all in reliability. He told me as a cop I was crazy for not using that gun. I quickly ended the discussion by telling him that politics lost the Vietnam war, not the M16. I also explained that the school I went to teaches that after the third magazine change you either break contact or call for Air Support. There is not feasible or plausible explanation for having to send 2000 rounds down range in a fire fight from a M16/M4/AR15. Period. I told him that when I was in the desert I carried 180 rounds for my M4, and 80 rounds for my DMR/SASS if I had it with me. Needless to say he didn't know the number of magazines or weight of a combat load out with 180 rounds vs 2000 rounds.

So, back to the AR reliability issue.

First you need to understand that there are two types of failures. There are Stoppages and Malfunctions. A stoppage is a failure of an automatic or semiautomatic firearm to complete the cycle of operation for reasons other than mechanical failure. A malfunction is a stoppage due to mechanical failure of the weapon, feeding device, or ammunition. So, now that we have established the types of failures lets talk about them an how the two gas systems relate to them.

First the Malfunction.

Shit breaks. Pretty straight forward, isn't it? If it is used enough, stressed enough or just the right way, used wrong, abused, just gets mad at you or wants to make you look stupid for not having spare parts, it will break. Only the gun gods can control that. The most common malfunctions I have seen involve the magazine and extractor. Cheap aluminum magazines get bent, dented or otherwise abused and then your SOL. We use to get our asses chewed for letting M16 magazines hit anything other than grass or sand (and sand ain't good either). Thankfully in recent years companies like Magpul has made drastic improvements in the AR magazine, making it more sturdy, reliable, and grunt/cop-proof. Believe me, if it can be broken give it to a cop or grunt and have them “try it in the field”. It'll get broken.

The problem with the extractor is not the extractor it's self. Its the spring. It becomes weak after time, thus causing the extractor to become weak. This causes all types of problems- Failure to extract and double feeds being the two main ones. The solution is to use an extra power or enhanced extractor spring and O-ring.

As far as the action spring goes I run a Wolff extra weight spring and a H2 Buffer. This does a few things for reliability and accuracy. First it provided extra force behind the bolt carrier and bolt as the action closes. This facilitates more reliable feeding from the magazine as well as feeding thought the throat and into the chamber. It also provides as a secondary function recoil dampening, thus facilitating faster follow up shots. In full auto guns it will also slow down the rate of fire, making the gun more controllable in full auto.

I've seen other parts malfunction also, but most were a result of human intervention. If you use a firing pin as a punch it will get jacked up and may fail. If you try to file carbon off of the back of a bolt it will get scarred up and may fail. If you use a butt stock to beat a cleaning rod down a barrel trying to get out a squib it can break and thus may fail.

It has also been my experience that major components don't just break. I have NEVER seen a bolt break, so why carry an extra one in the pistol grip? Bolt carrier keys, when properly installed and staked, do not just come loose; thus the purpose of staking is revealed. Here is a hint- JB Weld does not belong in your AR field repair kit and it don't go on a bolt carrier (Yeah, I've seen it).

And then there is the Stoppage.

Stoppage is due to fouling, dirt, and lack of or improper lubrication. Now first let me say if you are a piston guy and I offend you, you'll get over it. I'm a passionate guy and can come across as an ass at times. You have been warned.

There is one reason for a stoppage- lack of proper maintenance. This whole gun thing is pretty simple. Buy gun, Clean gun, Shoot gun, Clean gun. Repeat as necessary and as your female companion will allow. Or for those who are not tracking-CLEAN YOUR GUNS! This should be simple enough, but I'll go a little more in depth.

The first thing you should do with any gun you bring home is clean it. I personally do a complete disassembly. I inspect all parts and components, especially on a used gun. Next I scrub, scrub, scrub. I use a special mix of solvents that I have been using for several years. You can use CLP, Remoil, or whatever gun cleaner you prefer. And all you need to do is field strip. Complete disassembly is not required. The gunk on most guns from the factory are not there as a lubrication primarily. It is more of a preservative and corrosion preventative put on the gun to protect it during shipping and storage.

Obviously if you shoot a gun you should clean it. What most people don't do is clean a gun prior to shooting it. If you have had a gun in the safe for a few months and are planning to shoot it the next day you need to clean it and make sure it is properly lubricated. Lubricants do not last for ever, even in storage. Maintenance on the AR is the key to reliability, as it is with every firearm.

Operating Cycle of a Direct Inpingement System

Now, when you think of the operation of the rifle, how does a gas piston solve issues of stoppage caused by poor maintenance? The operating system inside the upper receiver is virtually the same. The only difference is the bolt carrier key and gas tube are replaced by an operating rod and bolt carrier push plate. All of the moving, sliding, rotating parts are still there. In fact, you have added a spring and piston into the mix at a bare minimum. Some piston systems incorporate up to 4 moving parts. There are no tolerance increases and no elimination of moving parts in the upper. It still needs to be cleaned and lubricated. And it costs $400.00 more. My two springs, buffer, and o-ring cost a total of about $40.00. Oh, and you still need to do this in a gas piston gun too.

Some argue that the Direct Impingement system injects carbon fouling into the upper receiver. Ok, maybe you'll just have to spend a little extra time cleaning. Even after 2000 rounds a properly lubed and maintained gun should still be reliable unless those 2000 rounds were loaded with crude oil and dinosaur bones. There isn't that much crap spewed into the action through the gas tube.

Operating cycle of a Gas Piston System

I will concede that the first M16 issued to the troops in Vietnam were rushed into service and our troops payed dearly because of its reliability issues. But that was over 40 years ago. Many improvements have been made to the system including the addition of the forward assist. If the M16 was such a problem it would have been replaced already.

The bottom line is weather you choose to run a Direct Impingement gun or a Gas Piston gun you need to follow a few simple rules to help your gun keep you alive.
1.Routine maintenance. Clean your gun.
2.Keep the Ejection Port Cover closed. It ain't there to engrave cool shit on the inside.
3.Use a muzzle cap.
4.Keep a magazine inserted or keep the magazine well covered.
5.Slap the forward assist every now and again.

Weapon, body, gear, chow. In that order. Those are your down time priorities. Your gun will take care of you if you take care of it. You rely on your car to get you to work so you maintain it. Do your gun the same.

I guess I made it fairly obvious I'm not a gas piston fan and hopefully I explained myself fairly well. I just don't buy into the hype but to each his own. Next time you hear a guy say he had issues with his rifle in Iraq or Afghanistan ask him what happened. Most will blame the sand or dust. A gas piston ain't gonna stop sand and dust from binding an AR action. If you get enough crap in there to have a stoppage, Piston or Impingement, you got issues.

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