M4 and reliability: Debunking the piston myth

[thesheepdog]

^^^^^ Hahaha! So true!!

 

[theinvisibleheart]

Slamfire, re: early M16s in service

I agree.

Quote:
Some of the Khmer Rouge guerrillas kept on using cannibalized M16 FWIW, although I'm not sure if it's still so.
Cash strapped insurgencies will use anything they can get their hands on. Buds who served in Vietnam told me of the different firearms found in VC caches. You could find anything, from French shotguns with busted stocks, to, anything.

Buds who have come back from Iraq have said the same things about weapon caches there. I can't find the pictures of chromed and gold plated AK's, would love to post those. Also there were WWII German arms.

Anyone ever handled a “Khyber pass” weapon? If it goes bang, it will be used until it stops going bang.

Well heeled outfits, like Mexican Drug lords, are getting train loads of new US weapons directly from the Mexican Army. ( I bet they have stingers.) In twenty years or so we will see the worn out survivors being passed around insurgencies world wide.

 

[theinvisibleheart]

HorseSoldier, re: post

Considering the number of adoption of gas piston system for elite units using M4 platform, you would expect SOME (less than half) not to be happy.

As for HK416 being a HK marketing thing, then how come MOST new post-1990s small arms being adopted by countries worldwide is NOT gas impingement?

Is China adopting new gas piston QBZ due to HK influence?

Is Greece adopting gas piston G36 due to HK influence?

Is Ireland adopting gas piston Steyr AUG due to HK influence?

Is IDF adopting gas piston Tavor due to HK influence?

Why is Japan's small arm (Type 89, based on AR-18) gas piston? Again, due to HK?

Why is Singapore's new service small arm gas piston? Again due to HK influence, LOL?

As for experience, no one person's experience is 100% and/or complete. That's why you have engineering text on small arms design/principles.

You can't understand small arms by experience alone. If that were the case, you need only auto drivers for automobiles(no automotive engineers) and all NASA would need would be astronauts, LOL.

Quote:
then how come so many of current/former users of M4 are trying to use HK416, including US military units?

Like US Army DELTA, Australian SOC, German KSK, GROM, etc.?

Because they liked M4 too much, LOL?
CAG ("Delta" if you're living in the 1990s) switched to HK416s for the very specific reason of needing weapons that ran well with suppressors on them and with very short barrels. It's been a mixed blessing. Having been assigned to a unit where several of our ODAs were issued 416s, I've seen professional gunfighters turn their 416s in and switch back to M4A1s because, all the hype aside, HK turned out a mediocre product. (The specific issue with ours was really shoddy accuracy -- search HK416 and you should find some threads where I go into details on those 5 MOA wunderwaffens.)

Same for most anyone else outside the HK marketing sphere (so what KSK fields -- who cares? last I heard they actually had H&K corporate sponsorship . . .) trying out the 416s. And same, from what I hear, with mostly finding them not without their flaws -- though still better than the G36/XM8, but that's a fairly low bar to top for durability and accuracy.

Quote:
As for HK91/G3 getting dirtier than AR/M16/M4, obviously, bigger/larger caliber/bullet has more gas propellant/residue per round, right, LOL?
So this means you've never dealt with an MP5 or HK53, either then, I take it? Because a roller lock design getting dirtier than a DI design has nothing to do with relative caliber.

But, in any case, it seems like you can't be influenced by people who've got much more firearms experience than you do personally (including actual use of one or more of the weapons under consideration in combat), nor by inconvenient facts, so I'm inclined to agree with Bartholomew Roberts that there's not much point to continuing this discussion.

 

[theinvisibleheart]

Chindo18Z, re: post

sorry, but countries like Ireland, Singapore, Japan, Australia, Germany, etc. aren't exactly poor and can pretty much afford anything that they want.

In fact, much of the times, replacement system for gas impingement M16/M4 cost more, such as in the case of IDF's gradual adoption of Tavor instead of M16/M4.

And some of the most vocal cries for replacement of M4 comes from elite units.

Quote:
theinvisibleheart: If you check the list carefully, you'll notice that most of those countries, when they upgrade their basic assault rifles, are going from gas impingement system to gas piston system. E.g.,…Afghan National Army(AK), post-Saddam Iraqi Army(AK)
Neither the ANA nor the ISF have anyone who could spell Direct Gas Impingement vs. Gas Piston, much less appreciate the difference. The masses of their forces continue to use AKs out of economic necessity because:

1. Their nations were already awash with them (and the ammo) when we invaded
2. They have limited budgets and can’t afford to change

Their best units (the ones that actually capture and kill bad guys for a living) use M4A1s.

 

[theinvisibleheart]

Quentin2, re: post

I don't favor gas piston AR.

I think it's cleaner and easier to adopt a system that was designed as a gas piston gun from the start(like AR-18, G36, Tavor, Howa Type-89, HK XM8, etc.) rather than doing a gas piston conversion on AR15/M16/M4 platform.

Regarding accuracy, I think you don't understand how big silhouette or human torso is.

Most people's torso is at least 20 INCHES WIDE. That means 2MOA gun can hit the torso at 1,000 yards, well in excess of viable range of .223 cartridge.

theinvisibleheart, you glossed over the issue of proprietary parts in the piston AR. As you know most AR piston designs will become orphans in the coming years, there are just too many proprietary designs which means there must be a shakeout and standardization. That's the way of the world. So who's gonna win and do you think you chose the winner? If not you'd better pick up parts while they're still around. Does Ruger sell spares? Do others? If not then the best spare part you could have in dire circumstances is a complete DI upper.

The "advantages" of the piston AR tend to fall in ballpark of the "new and improved" slogans you see in advertising. Usually it's just hype to get more bucks out of your pocket and into someone elses. Why else would they be foisting off a $300 solution that's more complex, less accurate, weighs more and consists of more parts to replace a $15 gas tube that works?

Anyway I'll let you have the last word, you've obviously got more free time than I do.

 

[theinvisibleheart]

Brenten, misunderstanding

I think you misunderstand.

I'm not PRO gas piston nor ANTI gas impingement system.

I've shot very high round count(thousands) through gas impingement system in matter of hours/days in very, very adverse environment(mud/sleet/ice/rain/water/sand/grit) w/o one single problem, while witnessing other people's gas impingement system having problem.

In British military trial for sniping autoloader, gas impingement LMT 308 MRP came out on top both in terms of reliability and accuracy, beating gas piston system.

Does that mean gas impingement is superior to gas piston or even equal in reliability? Unfortunately, no. You can overcome the problem to some extent by overengineering the parts and by choosing situation like precision shooting(DMR type sniping/low volume of fire).

But for application such as assault rifles/light machinegun/heavy machinegun/etc., it's not a good application. Remember, volume of fire in sniping is low while in the case of assault rifles/machinegun, it's high or could be high, and in very adverse environment.

I've shot several cheaply made AR-180 that was 30+ years old and it runs much cooler and cleaner than modern gas impingement system. You can overcome the cooler/cleaner system of gas piston by using more expensive parts in gas impingement system, but if you do the same for gas piston system, again, over long term, gas piston will come out ahead.

Haha, this has gotten hilarious. theinvisibleheart, you obviously have a unusual love of the ar piston design and will defend it to the death regardless of whether you are wrong or right.

Fact is simple. The problem with DI has never been DI. It never was, but you ignore all facts and continue ranting and no one is listening any longer.

I will find a test someone did for you regarding accuracy. They tested the same gun with a piston upper and with a DI upper of like quality and the DI upper was more accurate. But I am sure you can come up with an excuse.

Piston is not a solution but an alternative. It has some advantages and it has disadvantages, you only see the advantages and that is one, little gas fed into chamber and bolt from di system. That's it. The bolt is designed to take heat, so it cannot be destroyed by heat.

The disadvantages are more important to me. MORE MOVING MASS, means more WEAR and TEAR in the piston gun. MORE MOVING PARTS means more things to break. The recoil spring in the piston gun is right above the barrel. Springs are small pieces of metal and heat affects them much more than other parts. Not good to have an exposed spring above a barrel, like LWRC and POF and most others do. Even the old design of the AK encloses the spring, the Russians new better, lol. The piston is not on par with the DI gun no matter how many posts you hash out.

 

[theinvisibleheart]

.22LR, re: post, latest

yup, the only thing I have experience with is Daisy Red Ryder/Airsoft, LOL(humour). And I'm chubby, LOL.

In general, it's not intelligent to argue things based on:
- I know better because I have done so-so things
- I know better because I have so-so special training
- I know better because I have so-so certification
- I know better because I attended so-so school(s)

for some reason....
This is all I can think of when discussions of what the military should do come up:

 

[Dobe]

Regarding accuracy, I think you don't understand how big silhouette or human torso is

The problem is that full torsos are rarely offered as a target any where except a firing range. Many times, a head shot is it.

Your entire premise is that because the AR bolt gets hotter, and dirtier, it can't very well be reliable. What you are missing (or avoiding) is that the AR is reliable enough. For example, if an AR can sustain 2,000 - 3,000 rounds of continuous fire without minor cleaning/ lubing, how much more does a soldier need?

Accuracy and modularity are two of the AR's greatest strengths, as well as its reliability. Reliability is important, but if you were looking for total reliability, then an automatic weapon wouldn't be the one of choice.

 

[theinvisibleheart]

Dobe, re: post

In assault rifle role, most gas impingement systems wouldn't go 2,000-3,000 rounds w/o problem in Middle East/Afghanistan.

Firing 2,000-3,000 rounds in a clean range and taking a periodic break is not the same thing, unfortunately.

In assault rifle, reliability always come before accuracy.

FWIW, that 2MOA was tongue in cheek. Most modern gas piston system today does better than 2MOA.

Let's say human head is 10 INCHES WIDE. With a 2MOA gun, you can still hit it at 500 yards.

How far is far enough? Again, you are stretching the ballistic limit of .223 cartridge.

Quote:
Regarding accuracy, I think you don't understand how big silhouette or human torso is
The problem is that full torsos are rarely offered as a target any where except a firing range. Many times, a head shot is it.

Your entire premise is that because the AR bolt gets hotter, and dirtier, it can't very well be reliable. What you are missing (or avoiding) is that the AR is reliable enough. For example, if an AR can sustain 2,000 - 3,000 rounds of continuous fire without cleaning, how much more does a soldier need?

Accuracy and modularity are two of the AR's greatest strengths, as well as its reliability. Reliability is important, but if you were looking for total reliability, then an automatic weapon wouldn't be the one of choice.
__________________
But yet those 1911's of WWI, II, Korean, and Vietnam era worked "right-outa-da-box".
Imagine that. Sounds more like a quality control issue of later years than an obsolete design. Dobe

 

[Dobe]

n assault rifle role, most gas impingement systems wouldn't go 2,000-3,000 rounds w/o problem in Middle East/Afghanistan.

You are basing this off of.....?

And I would like to see any proof that all of the fore mentioned piston guns will maintain a 2 MOA.

 

[kraigwy]

Regarding accuracy, I think you don't understand how big silhouette or human torso is.

And you have no ideal how easy it is to miss a silhouette target or a human torso.

In an controled enviorment, using trained snipers, according to this study they hit the e-silhouette about 27% of the time.

Sniper Weapon Fire Control
Error Budget Analysis
ARL-TR-2065

Table 7. Error Budget M 118LR

I've had people show up with my high power clinics with AKs and SKS, very few are able to keep 50% of the shots in the scoring rings of the NRA 100 yard reduced targets.

But like I said, its a moot point, if in the military we shoot what they tell us, if we are shooting on our own, buy what you want for the type shooting you do. I'm an high power Servicer Rifle shooter, I'll stick to the AR.

 

[theinvisibleheart]

Dobe, re: post

According to US military, most soldiers in Middle East/Afghanistan clean their weapons(M16/M4) at least once a day, and yet, they get 19% and higher rate of stoppages/malfunction in combat(actual percentage is higher due to survivorship bias).

Survivorship bias(statistic) means when you take a sample, by nature of sampling, you can only interview the survivors, so the data you get is distorted downwards.

Sand/dust in Middle East is very fine, almost like powder and gets into everything. Weather/environment in Afghanistan goes in extreme.

Wear rate for everything, from choppers to tanks to vehicles, is accelerated.

If anybody can come up with a solution whereby 99% of gas impingement small arms WILL function 99% of the time w/o cleaning for 2,000-3,000 rounds in Middle East/Afghanistan, I'm sure US gov, as well numerous other governments, like Israel, would be interested in hearing.

As it is, the posters on this thread are even disputing basic facts such as:
- not even understanding what survivorship bias is
- combat accuracy is such that accuracy edge of gas impingement system over gas piston system matters
- assumption that M4A1 can go 2,000-3,000 rounds w/o cleaning in Middle East/Afghanistan

Quote:
n assault rifle role, most gas impingement systems wouldn't go 2,000-3,000 rounds w/o problem in Middle East/Afghanistan.
You are basing this off of.....?

 

[theinvisibleheart]

kraigwy, re: post

obviously, if operator error is >> than weapon's innate accuracy, then operator accuracy matters way more than weapon's innate accuracy.

In plain English, differences in accuracy b/w gas impingement system and gas piston doesn't matter, because:

1. operator error is likely to be bigger
2. target is more than large enough, provided the shooter do his part

THINK!

Quote:
Regarding accuracy, I think you don't understand how big silhouette or human torso is.
And you have no ideal how easy it is to miss a silhouette target or a human torso.

In an controled enviorment, using trained snipers, according to this study they hit the e-silhouette about 27% of the time.

Sniper Weapon Fire Control
Error Budget Analysis
ARL-TR-2065

Table 7. Error Budget M 118LR

I've had people show up with my high power clinics with AKs and SKS, very few are able to keep 50% of the shots in the scoring rings of the NRA 100 yard reduced targets.

But like I said, its a moot point, if in the military we shoot what they tell us, if we are shooting on our own, buy what you want for the type shooting you do. I'm an high power Servicer Rifle shooter, I'll stick to the AR.

 

[Dobe]

As it is, the posters on this thread are even disputing basic facts such as:
- not even understanding what survivorship bias is
- combat accuracy is such that accuracy edge of gas impingement system over gas piston system matters
- assumption that M4A1 can go 2,000-3,000 rounds w/o cleaning in Middle East/Afghanistan
]

I believe you give yourself too much credit, if you assume other poster do not know what survivorship bias is. If you yourself can not prove the statistical importance of SB for this situation, then its only purpose in bringing it up is to what? Impress us?

Next - I am still waiting for you to even prove 2 MOA for all of the piston guns you hail so highly.

What you need to understand is that everyone has a natural area of wobble while shooting. If you are standing and shooting a target at 100 yards, and your rifle's best MOA is 4", and your area of wobble is 4", then your group size becomes 8".

Anything you can do to increase accuracy is important as long as it doesn't reduce acceptable reliability, acceptable weight, and increase cost beyond acceptance..

 

[KChen986]

LWRC M6A3,

3 Shots, Irons, 100 yards. Probably a fluke, but...

LWRC Bills them as 1.5 MOA guns.

 

[theinvisibleheart]

Dobe, re: post

Most assault rifles today do better than 4MOA and when countries worldwide test/accept it, falls within the acceptable combat accuracy parameters, be it Switzerland, China, Japan, Germany, etc.

Most countries' new assault weapon small arms are gas piston, not gas impingement, and they judge the combat accuracy/reliability to be acceptable for their own needs.

If most M4 in use in Middle East/Afghanistan can go 2,000-3,000 rounds w/o cleaning and suffer zero malfunction/stoppages, I would really appreciate the engineering/operating insight.

As for survivorship bias, since some of the pro-impingement posters started reasoning by degree/experience(have so-and-so degree/experience/attended school/etc.), I was surprised that nobody mentioned survivorship bias since that's something basic in statistic, LOL.

If one's educational/experience is so august, as some of the pro-impingement posters in this thread claim, then they should have it caught it very early on. I wonder why they didn't, LOL?

Real value of education/degree/experience/etc. is enhanced ability to reason and think, not to boast about it in online forums, LOL. I wonder why it is not so on this forum?

Quote:
As it is, the posters on this thread are even disputing basic facts such as:
- not even understanding what survivorship bias is
- combat accuracy is such that accuracy edge of gas impingement system over gas piston system matters
- assumption that M4A1 can go 2,000-3,000 rounds w/o cleaning in Middle East/Afghanistan
]
I believe you give yourself too much credit, if you assume other poster do not know what survivorship bias is. If you yourself can not prove the statistical importance of SB for this situation, then its only purpose in bringing it up is to what? Impress us?

Next - I am still waiting for you to even prove 2 MOA for all of the piston guns you hail so highly.

What you need to understand is that everyone has a natural area of wobble while shooting. If you are standing and shooting a target at 100 yards, and your rifle's best MOA is 4", and your area of wobble is 4", then your group size becomes 8".

Anything you can do to increase accuracy is important as long as it doesn't reduce acceptable reliability, acceptable weight, and cost.

 

[Dobe]

As for survivorship bias, since some of the pro-impingement posters started reasoning by degree/experience(have so-and-so degree/experience/attended school/etc.), I was surprised that nobody mentioned survivorship bias since that's something basic in statistic, LOL.

If one's educational/experience is so august, as some of the pro-impingement posters in this thread claim, then they should have it caught it very early on. I wonder why they didn't, LOL?

Why they didn't, they will need to answer, but since I did, I'm wondering why anyone would bother to use it as an argument knowing it will surely be turned on them. In other words, don't quote the ills of SB, without proving the statistical relevance.

 

[theinvisibleheart]

Dobe, re: post survivorship bias

it sounds like you still don't understand what survivorship bias is.

It means in this circumstance, reported malfunction rate of 19% in combat is actually underreported so that the actual incidence is higher than 19%, LOL.

You see, if M4/M16 malfunctioned in combat and users died or got severely wounded in combat, then they are likely to be underreported in CNA study since they were not available for interview.

Many of the pro-impingement posters in this thread seem to be unaware of statistics, such as minimum sampling size or how to do a multifactor analysis despite claims of august education/degree/experience/etc.

Quote:
As for survivorship bias, since some of the pro-impingement posters started reasoning by degree/experience(have so-and-so degree/experience/attended school/etc.), I was surprised that nobody mentioned survivorship bias since that's something basic in statistic, LOL.

If one's educational/experience is so august, as some of the pro-impingement posters in this thread claim, then they should have it caught it very early on. I wonder why they didn't, LOL?
Why they didn't, they will need to answer, but since I did, I'm wondering why anyone would bother to use it as an argument knowing it will surely be turned on them. In other words, don't quote the ills of SB, without proving the statistical relevance.

 

[Dobe]

it sounds like you still don't understand what survivorship bias is.

I absolutely understand what it is, and you are using SB as a safety net the same way that a 1st year stats major would.

Prove the relevance. SB is a ghost, if you cannot attach numbers to it. That is the problem with SB.

 

[Chindo18Z]

And some of the most vocal cries for replacement of M4 comes from elite units.

Wrong. Almost everyone out here actually killing folks has gone to the M4 platform while discarding G36, SIG, AUG, AK, etc. There is certainly no institutional dissatisfaction with the M4A1 among US SOF nor a clamor for a replacement. With all due respect, you have absolutely no idea what you are talking about regarding this point.

As a longstanding member of one of the American units you've referenced, I've worked shoulder to shoulder (in combat and training) with most of the other "elite" units you have casually name-dropped. GROM, Delta, Singapore Army, IDF, KSK, AUS SAS, Afghans, Iraqis, etc.

Regarding accuracy, I think you don't understand how big silhouette or human torso is.

Your statement shows a complete lack of understanding as to what happens in a firefight vs. a flat range. It's like listening to a virgin pontificating about sex...entertaining, but dreadfully off the mark.

You can't understand small arms by experience alone.

Conversely, you'll not gain serious understanding of military small arms through the reading of design principle textbooks or Wikipedia entries either. It actually helps to go out and shoot a few folks who are firing back at you. I trust end-user data (including my own) ahead of the theoretical ruminations of an engineer concerning machine performance. The engineer tells me what he designed the weapon system to do and what performance should be expected. The end user tells me what actually happened when he used the weapon to turn someone's pumpkin into a canoe. It's a holistic approach to selecting the right tool for the job.

In general, it's not intelligent to argue things based on:
- I know better because I have done so-so things
- I know better because I have so-so special training
- I know better because I have so-so certification
- I know better because I attended so-so school(s)

It's also not generally intelligent to argue a topic with subject matter experts when you are demonstrably not one of them.