piston vrs gas ar

TSE_Justin said:
HK's MR223/416 is probably the smoothest piston AR I have ever shot, so far.
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+1
As for carrier tilt it's a non issue unless putting high rd counts through your rifle that no one does here, at least not with HK made rifle for the most part... I think most of these cases that arise were of the few and not the norm...

Kevin B knows more on these issues..

DI is fine and I love it, but for cleaning your rifle, i like the fact that the piston carbon build up is mostly concentrated in one area, as oppose to the a DI system..

I think for big armies the Piston system might be better way to go, since the armors i have seen don't really keep up with the maintenance schedule on a DI system the way they should, or for any system for that matter..Perhaps the Piston might be more bad maintenance friendly...where the DI is not...

If anything it seems to me that you are just really trading for different things on the two systems...Different parts wear on a DI than a piston...

I bought the MR223/MR308 because they were available at the time and were HK rifles & especially for their barrels they offer..I would have bought it if they made it in DI as well, I wanted them especially because of the AR config they were made in, and was HK a company that i trust and believe in...

The KAC SR15e3/SR16 seems like the ticket in 223/556 though for most people, for the money I say the HK417/MR308 seems like the best for the 7.62x51mm/308 semi-auto selection..

There are so many companies making a Piston system, that for me it is a turn off, for there is no commonality of parts, not like the traditional DI/AR system that has been out for 50 years..That is why i would go HK, the other companies well how long will they be around for, and where will you get parts if they ditch the piston system...?????
 
PWS piston guns come with the PWS enhanced buffer tube with extended lower lip to help reduce carrier tilt.

The PWS guns are questar are priced very reasonably. they come with BU(plastic)Sights, and the enhanced buffer tube. I had to retrofit the PWS EBT on my LMT piston gun
 
If Piston AR's are so bad (I'm not talking about the cheap conversions out there, but dedicated guns like LWRC and HK) what about the Marine's IAR?
Basically a HK 416 with a heavy barrel. Kicked ass on the other weapons it was tested against. The Marines shot the shat out of their test guns and are using it in a fire support role, so high round count and hot barrels.
Whether you agree with them going from a belt fed LMG to a mag fed system is a whole other argument.
The fact is the piston HK IAR is performing outstanding and they are buying more.

Rich
 
I think the issue is pretty moot on a semi if you aren't using cans. I clean my ARs as often as my SAN, which is not very often. It takes literally 10 minutes to do a field strip and quick clean/lube.

DI: Dirtier, simpler, lighter, more inherently accurate, parts commonality out the wazoo
Piston: Cleaner, heavier, more complicated, less inherently accurate, more proprietary components

Pick your poison.
 
The proliferation of piston ARs on the civilian market has more to do with marketing than any real need. They don't fix anything and they cause a number of problems in the proccess.

Now if you are going to be running a suppressor most of the time they make sense.
 
So what problems are the US Marines having with the HK 416 IAR's that they are fielding? So far it's 10's of thousands of rounds in the trials and going strong.

Some piston kits are crap, and some of the dedicated designs are very good.

I know it's a tough pill to swallow for some people that the piston is a better gun. How much better is up to debate, worth the extra cost is also debatable but they are an overall improvement to a very old design. All the drastic "carrier tilt" issues that some think will destroy the gun / upper receiver quickly aren't showing up in the IAR.

Rich
 
Left handed AR? Why? Charging handle is on top right in the middle. Case deflector prevents cases from hitting the shooters face. Even the AR's with no case deflector rarely cause a problem of this kind. I have shot only regular AR's on both semi and automatic and have never had cases hit me.
Moreover I think regular AR's would be easier to get parts for.
 
I really find some of the comments here about piston AR`s to be rather astonishing....It`s almost like people are commenting on the superiority of a Model A car to a Lexus (OK, a little much, but still)....It appears some people are basing their opinions when the piston conversion kits came out years ago...Things have changed people....
The piston adds weight?...I have compared the two, and I can barely tell the difference...
Inaccurate?.....My M4 against several other pistons shows no difference...
More moving parts?.....Aside from the fact it`s just a couple of extra parts, so what?....The Garand has more moving parts than a bolt action Springfield, should America have then stayed with the Springfield during WW2?....
Carrier tilt?....Really, is the gun going to shake apart after a few thousand rounds?.....
More recoil?....Are you serious, Nancy?....
Come on people, join the 21st century....Progress means keeping in touch with the latest technology that improves on the old...
I swear, some people here would have you believe that staying with a pocket pager system is superior to today`s blackberry`s.....

"They don't fix anything and they cause a number of problems in the proccess."...Gawd, can you believe this crap?...
 
Rich LPS said:
So what problems are the US Marines having with the HK 416 IAR's that they are fielding? So far it's 10's of thousands of rounds in the trials and going strong.

Some piston kits are crap, and some of the dedicated designs are very good.

I know it's a tough pill to swallow for some people that the piston is a better gun. How much better is up to debate, worth the extra cost is also debatable but they are an overall improvement to a very old design. All the drastic "carrier tilt" issues that some think will destroy the gun / upper receiver quickly aren't showing up in the IAR.

Rich
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The IAR is deployed. My friends south of the border tell me that other than the accelerated locking lug wear typical of piston ARs they seem to be working well and proving that you get more hits with individual aimed shots.

Funny how there is a chance that now the barrel extension and bolt can wear to the point of requiring a new bolt and barrel assembly due to headspace issues while the barrel is still good to go. Solve a "problem", create a problem and pay more for it.
 
In a 10 december 2009 letter to secretary of defense robert gates and chairman of the joint chiefs of staff admiral mike mullen, co-signed by chairman of the house committee on armed services representative ike skelton (d-mo) and chairman of the house subcommittee on readiness representative solomon ortiz (d-tx), the congressmen raised the issue of the m4, citing their concerns that although the m4 "routinely rank lower than other military weapons in testing, they are still being issued as the army's weapon of choice."

what the congressmen seem to be referring to are the results of the u.s. Army test and evaluation center's (atec) september-november 2007 extreme dust test 3, which press reports leapt on as an indication of the m4's purported shortcomings. In the test, where ten sample m4s drawn from army inventory competed against ten samples each of heckler & koch's hk416 and xm8 and fabrique national's mk16 scar, the weapons, with an initial coating of heavy lubrication applied, were placed in a dust chamber for 30 minutes and then fired to 120 rounds before being returned to the dust chamber for another half hour. This process was repeated to 600 rounds, at which point the weapons were wiped down and another coat of heavy lubrication was applied.29 firing continued in this way to 6,000 rounds per weapon.

Raw test data made available to the press indicated that, collectively, m4s experienced 863 low-impact and 19 high-impact stoppages over a firing schedule of 60,000 rounds—the other weapons experienced significantly fewer stoppages—but atec's final report, which appeared in february 2008, noted that "m4 performance . . . Was significantly different than in the previous extreme dust test in which it participated," and that a separate effort was under way to investigate the reasons.

According to officials at colt, those reasons included the fact that six of the ten m4s drawn for the test did not meet the minimum rate of fire of 700 rounds-per-minute mandated under mil-spec iaw mil-c-70599a(ar), which requires a cyclic rate of fire of 700 to 970 rounds-per-minute. The m4s used in dust test 3, delivered to the army in june 2007, met mil-specs when delivered; however, together the ten drawn for the test from the u.s. Army inventory averaged only 694 rounds-per-minute.30 while performing comparably with the hk416, xm8, and mk16 in all other respects, the m4 carbines used in the test experienced a large number of failure-to-feed and failure-to-extract stoppages.31 colt says this is because of the sub-mil-spec rate-of-fire of the test weapons.

Colt also states that atec's testers were unfamiliar with the m4s' 3-round burst configuration which, depending on the position of the cam, will sometimes fire 1 round or a 2-round burst before firing a 3-round burst. This unfamiliarity, said colt, led to single rounds and 2-round bursts being counted as stoppages. With the exception of the m4s, all other weapons tested were fully automatic with no 3-round burst provision. Further, colt points out that the test itself did not meet mil-spec 810f and "was not repeatable."

in response to what colt described as "the premature media reporting" of the raw test data, program executive office soldier suggested that colt conduct its own extreme dust test. So colt contracted a dod-certified testing agency, stork east-west technology corporation in jupiter, florida, to conduct its own dust test according to mil-spec guidelines. In this test of ten m4 carbines, which was conducted under a protocol identical to that used in extreme dust test 3, only 111 stoppages were reported.
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In the original test.
XM8: 127 stoppages.
MK16 SCAR Light: 226 stoppages.
416: 233 stoppages. (117 by one rifle)
M4: 882 stoppages.( In rifles that probably needed new gas rings)

Colt M4s as supplied by Colt 111 stoppages.

The numbers produced by the test are pretty much worthless, but great for fueling the whole pistons are more reliable argument.
 
heckler said:
Most everyone has nailed the issue with piston systems dead on.There is only one piston system I personally would consider in an AR platform and that is the POF,as its about half way between the two designs and had had next to Zero problems. A truly well thought out system,but mainly designed for full auto. Check out vidio on their site for further explanationhttp://http://www.pof-usa.com/main.htm
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POF's are great units. Being hearing really good things accuracy wise on them.
 
Does he think a piston AR15 will make HIM happy?
If yes: buy a piston AR15.
If no: do not buy a piston AR15.

There is no reason to purchase a piston AR15 over a DI AR15 unless it makes you happy.
There is no further reason needed to purchase a piston AR15 other then that it makes you happy.

That's my take on it.
 
Cpt.Flan said:
Gaz all the way.

Do you guys know why they created the piston system?

2 hints... Full auto... HK416...

You really don't need to run that bolt carrier that cold in a semi automatic AR. Yes it can run cleaner but for all the disadvantages it is worth it? I don't think so IMHO.

It will most probably never get hot enough. I would only suggest a piston system for a very short AR ( 7" or 10" ) to increase the reliability and functionality. Since the short gaz tube would put a lot of heat and pressure in the chamber.

With that said... Piston will f**k up the barrel harmonics and you will lose accuracy also.

Why pay more for a feature that will most probably not change anything for what you will use it for?


Cheers.
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:cheers:

Also one of the advantages of the DI is the handiness of the rifle. They are slimmer, lighter and better balanced than most piston systems.
 
Epoxy7 said:
:cheers:

Also one of the advantages of the DI is the handiness of the rifle. They are slimmer, lighter and better balanced than most piston systems.
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I'm guessing that you have not handled a PWS AR Rifle... sounds like you'd be pleasantly surprised by the weight, balance and dimensions. ;)

Mark
 
Airwolf said:
"They don't fix anything and they cause a number of problems in the proccess."...Gawd, can you believe this crap?...
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Yes.

When I see private operators like Blackwateret al or the SEALs or JTF2 using these by choice in a hostile environment, I'll go buy one.

Until then, it's a fad I am happy to take a pass on.

I don't doubt the PWS or Stag piston guns are nice and all, but the piston adds unwanted expense to a rifle that is already proven and not in serious need of improvement.
 
For civilian shooters, it doesn't make a whole lot of difference between DI and piston, in my rather worthless opinion. If you like to be on new trends and don't want to clean all that much, get a piston. If those aren't issues, get the one you think you'd like the most.

Or get them all. You're allowed to own more than one gun. For now, anyway.
 
The problem right now is that there is no such thing as "milspec" piston AR's. So each different manufacturer gets to come up with whatever solution they want while dodging everybody else's patents. From what I read, piston AR have a reputation by now of bent/broken/buster bolt carriers and chewed up uppers since cast aluminium don't deal so well with the massively increased forces involved.

Is a piston (of any kind) a "superior" design ? ABSOLUTELY !

Let's be honest here, it took half a century's worth of tinkering to make the DI AR what it is, from a jam-o-matic piece of crap to a semi-reliable firearm (if you put in the required hours worth of "maintenance").

As far as accuracy loss, I call bullfeces .... The AR with it's 5.56 cartridge was always a sub 300yds firearm, because that's what 1950's military doctrine called for. A shortish range weapon that allows a soldier to get out of ambushes alive, and machineguns can deal with the rest...

I don't see a piston driven AR being anything close to "reliable" for the entire life of it's barrel unless they both switch materials for the upper, and redesign the bolt carrier so that there is no flimsy "gas key" but a solid lump of metal able to take the stress.
 
Claven2 said:
Yes.

When I see private operators like Blackwateret al or the SEALs or JTF2 using these by choice in a hostile environment, I'll go buy one.

Until then, it's a fad I am happy to take a pass on.

I don't doubt the PWS or Stag piston guns are nice and all, but the piston adds unwanted expense to a rifle that is already proven and not in serious need of improvement.[/QUOTE

There are plenty of special forces using HK416/417 system, Blackwater was started by Seals, so there influences and preferences have carried over there, and are the dominating factor over there..As for JT2 they are not the end all be all anyways,a lot of that may have to do with other reasons, they already have a fantastic AR from Colt Canada, there barrels are fantastic to say the least. They were leading the way in CQB in my opinion for a short period and there snipers built a good reputation..I would say. But they have passed up great new pieces of kit at times as well, like everyone else...
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