View Full Version : Piston AR's. A Solution looking for a problem?
What is the point? We have already seen the downside: carrier tilt to start with.
I know that the AK is the most reliable assault rifle in exsistance. Are we just trying to mimic the piston in hopes that the AR will be just as reliable?
If this has already been discussed then I apologize, I'm new to this forum and just picked up my first AR in quite a while (DDM4)
Thnx
it has been discussed about a million times..
one thing, however- the AK is no more reliable than a well-maintained quality AR. less so, in fact.
Does the HK416 have a carrier tilt issue? Most seem to argue that the 416 is the M4/M16 taken to its highest level of perfection and it is a piston system. Personally, I think the 416 still needs a few more changes to achieve that status.
Does the HK416 have a carrier tilt issue? Most seem to argue that the 416 is the M4/M16 taken to its highest level of perfection and it is a piston system. Personally, I think the 416 still needs a few more changes to achieve that status.
pistons with their recoil springs at the piston (im sure there's a specific name for it) don't have carrier tilt, because they don't have receiver extensions or carriers that extend beyond the receiver.. AKs, M1As, masada, etc- tilt isn't an issue.
If my admittedly limited knowledge is not in total error, the design of our direct impingment system was intended to reduce weight from that of piston-operated guns. And that it does admirably. The trade-off is in getting crud more deeply into the bolt-carrier and allied parts of the mechanism, requiring greater attention to maintenance by the operator.
To me, direct impingment is what makes an AR an AR. Piston operated guns have their own merits. Neither is better nor worse, just different. IT'S ALL GUD!
pistons with their recoil springs at the piston (im sure there's a specific name for it) don't have carrier tilt, because they don't have receiver extensions or carriers that extend beyond the receiver.. AKs, M1As, masada, etc- tilt isn't an issue.
I don't think that's why they don't have carrier tilt, on the AK and M1A's (and FAL's and AK derivatives like the SIG 55x, Valmet, Galil, etc.) have carriers that ride on RAILS. This prevents tilting. In the AR, the carrier is just "free floating" inside the upper.
Not to mention that none of those have the same type of bolt lugs as on an AR which is yet another negative and wear point in these piston retrofit kits.
If someone wanted to make a REAL AR piston, they would need to use an internally railed upper and a slotted carrier. As for the bolt lug shearing, I don't know what could be off the top of my head but I'm sure someone smarter than me could figure something out.
I always wondered why the new "Armalite" didn't make a Masada-like upper for an AR lower that used the AR-180 piston system. They own the design, they have the tooling, and polymers are cheap and easy to work with. When you look at the original Masada/ACR design it recycled a lot of AR parts, just like the AR-18/180.
rifleman2000
09-03-09, 08:23
I don;t think it is a solution looking for a problem as much as it is a solution looking for a market. And it found one. I am sure that you can, given time, make a reliable piston-driven AR. Maybe they already have, I'm no expert on them.
But I trust my DI Colts without reservation. And I can clean them with my eyes closed, and know exactly where I need just two drops of oil to make them run like a champ.
the AK is no more reliable than a well-maintained quality AR. less so, in fact.
Out of curiosity, what do you base this on?
RetreatHell
09-07-09, 01:24
.....When you look at the original Masada/ACR design it recycled a lot of AR parts, just like the AR-18/180.
The first time I saw the Magpul Masada was on that famous episode of Future Weapons. If my memory is correct, didn't Mack say (and show a diagram of it too) that the only parts Magpul kept from the AR design was the barrel, trigger group, front sight post, and bolt (at least I think they said the bolt)?
I may be wrong here, but that's what I remember from that episode anyways.
Does the HK416 have a carrier tilt issue? Most seem to argue that the 416 is the M4/M16 taken to its highest level of perfection and it is a piston system. Personally, I think the 416 still needs a few more changes to achieve that status.
Yes, I have seen it first hand in a military unit running the 10.5" HK 416. It did not happen in every rifle but it did happen. I am not sure why it some rifles did not have this problem. Maybe round count played a role. Maybe too much play in upper/lower. I am not sure of something like an Accuwedge would fix the problem.
I don;t think it is a solution looking for a problem as much as it is a solution looking for a market. And it found one. I am sure that you can, given time, make a reliable piston-driven AR. Maybe they already have, I'm no expert on them.
+1
As someone who has owned a gas-piston AR, I wouldn't consider myself an "expert" on the subject, but I do feel I know a little about the issue. A few years ago I jumped on the bandwagon and bought POF upper; and it worked as advertised, reliable and clean. My big problem is that it weighed more than my other AR-15's, especially with my Surefire M900, and the recoil seemed heavier. Also the proprietary parts worried me; if anything ever broke, I would have only a single-source supply. Last year, I sold it, and took the proceeds and bought a top-of-the-line Troy upper to add to my lower, and have been very happy since.
Like others have said, I know the ins and outs of the AR well, and one can get spare parts for a conventional AR anywhere. Unless some manufacturer can win a significant military contract, parts will never be as ubiquitous as conventional AR parts, hence they will cost more and be more difficult to acquire.
While many gas-piston AR's are excellent, they don't represent such a quantum leap forward in technology that it would require every fighting man to get them. Especially since, in the end, it launches the same 5.56 rounds a conventional AR does.
Now, when someone develops a phaser, I will be first in line to buy one!
4thPointOfContact
09-07-09, 16:58
The first time I saw the Magpul Masada was on that famous episode of Future Weapons. If my memory is correct, didn't Mack say (and show a diagram of it too) that the only parts Magpul kept from the AR design was the barrel, trigger group, front sight post, and bolt (at least I think they said the bolt)?
I may be wrong here, but that's what I remember from that episode anyways.
I think they said "...just the front sight post.", but they were halfway kidding. The barrel is the same with a different extension in order for for it to use the QD system. The trigger group and pins are the same since no one has really ever complained about them being substandard.
[Edit:] In the pursuit of accuracy, I found this quote online and can see how it may have been attributed to Magpul "...'The best way to improve the AR-15 is to unscrew the front sight, and put a new gun under it." - Kevin McClung, aka Mad Dog. (which is just what MagPul did when they developed the Masada)' ..." I think that quote made it on to one of the promotional posters put put by Magpul in reference to the Masada.
Magpul advertising poster (PDF) (http://www.magpul.com/pdfs/masadaback.pdf)
Submitted for discussion sake: "M4 "Loses" Dust-test"
http://m4carbine.net/showthread.php?t=9789
"Newer carbines outperform M4 in dust test
Army Times
By Matthew Cox - Staff writer
Posted : Monday Dec 17, 2007 6:42:21 EST
The M4 carbine, the weapon soldiers depend on in combat, finished last in a recent “extreme dust test” to demonstrate the M4’s reliability compared with three newer carbines.
Weapons officials at the Army Test and Evaluation Center at Aberdeen Proving Ground, Md., exposed Colt Defense LLC’s M4, along with the Heckler & Koch XM8, FNH USA’s Special Operations Forces Combat Assault Rifle and the H&K 416 to sandstorm conditions from late September to late November, firing 6,000 rounds through each test weapon.
When the test was completed, ATEC officials found that the M4 performed “significantly worse” than the other three weapons, sources told Army Times.
Officials tested 10 each of the four carbine models, firing a total of 60,000 rounds per model. Here’s how they ranked, according to the total number of times each model stopped firing:
• XM8: 127 stoppages.
• MK16 SCAR Light: 226 stoppages.
• 416: 233 stoppages.
• M4: 882 stoppages."
In my opinion, that dust test doesn't paint a fair picture of the competition. In a competition of extreme attrition I will concede that the AR15 may not be the best choice.
If we were to make the contest a bit more realistic, my first question is who fires 60,000 rounds in a firefight? Our troops carry approximately seven magazines on them at one time? Maybe more, maybe less but lets say seven thirty round magazines, that means they can only fire up to approximately 210 rounds. I can understand wanting to see how long the AR15 can stand up to rapid firing in harsh conditions but 60,000 rounds is not just a pretty ridiculous number but an unrealistic number. Secondly, lets talk about the abuse it can take. For instance, the FN SCAR has had a couple of reviews come out from soldiers who got to play with it. It sounds like the buttstock is pretty fragile and prone to breakage. While I am sure it happens, I personally have never seen or heard of an AR15 buttstock break. Consider the small number of SCAR stories versus the extremely large number of AR15 stories and that is a little scary. The 416 has also had its share of problems despite, there is a very interesting article floating around about a PD in Arizona who couldn't get any of there 416s to work properly, HK couldn't find any problem with them, and instead offered to completely replace the rifles.
The point of the story is that there no perfect system. Actually in my opinion, when it comes to the AR15 the gas system is the least thing I worry about.
variablebinary
09-08-09, 03:43
I shoot my LWRC M6A1 more than my 6920 at this point, but I am not about to give up my 6920 either
If we were to make the contest a bit more realistic, my first question is who fires 60,000 rounds in a firefight?
The dust test involved 10 examples of each competitor that each fired 6000 rounds. hence the 60,000 round figure.
You can't lump all piston guns together either. The HK416 has served several years with Tier 1 units that may fire mores rounds in a month of practice than other units do in a year. It is certainly not 100% perfect, while other pistons seem to be lesser degrees of perfect--often with dramatic differences between individual ones and even individual units for the same model.
I shoot my LWRC M6A1 more than my 6920 at this point, but I am not about to give up my 6920 either
And I have a piston AR, but am considering replacing one of my DI ARs--a Noveske N4 Basic--with yet another DI AR--a Colt 6940.
variablebinary
09-08-09, 05:18
And I have a piston AR, but am considering replacing one of my DI ARs--a Noveske N4 Basic--with yet another DI AR--a Colt 6940.
I think most piston owners are in a similar situation. I don't think it needs to be all or nothing either way.
Though, truth be told, my AR15 piston collection probably wont expand beyond the one LWRC M6A1. Unless there is some utterly SICK deal on a 416 upper somehwere
For piston kicks I'll get more XCR stuff, add an ACR, a FAL and TAVOR in 2010.
.......For piston kicks I'll.......add.......a FAL........
Now there ya go!
it has been discussed about a million times..
one thing, however- the AK is no more reliable than a well-maintained quality AR. less so, in fact.
Ummm, bullshit! Don't let your bias distort the real world. Not saying that the AR platform isn't perfectly reliable but to say it is "more" reliable than the AK is just BS...
Ever seen Templars video where he fills it with sand at Blackwater and still cant get it to fail? Try the same thing with your AR and let me know how it works out for you...
The AK has its short comings (sights, safety lever and mag release) but reliability is not one of them. Keep in mind I am talking about a "quality" AK like you are with the AR not some CIA garbage.
RetreatHell
09-08-09, 10:53
....The M4 carbine, the weapon soldiers depend on in combat, finished last in a recent “extreme dust test” to demonstrate the M4’s reliability compared with three newer carbines.
Weapons officials at the Army Test and Evaluation Center at Aberdeen Proving Ground, Md., exposed Colt Defense LLC’s M4, along with the Heckler & Koch XM8, FNH USA’s Special Operations Forces Combat Assault Rifle and the H&K 416 to sandstorm conditions from late September to late November, firing 6,000 rounds through each test weapon.
When the test was completed, ATEC officials found that the M4 performed “significantly worse” than the other three weapons, sources told Army Times.
Officials tested 10 each of the four carbine models, firing a total of 60,000 rounds per model....
I don't think that test performed by ATEC is very realistic either. For instance, in the middle of a hellacious firefight I was in back in 2003 in Iraq, during a very brief lull in the fight, I reached into my right cargo pocket and grabbed the small bottle of CLP I always carried in there and squirted a large amount of the liquid into my bolt carrier group.
And during the whole invasion, from Kuwait to Baghdad, myself and my fellow Marines always constantly kept our weapons clean. And it's not like it was a hassle to clean them and maintain them, as we were used to cleaning them all the damn time since boot camp anyways, and it took just a few minutes to give it a good field cleaning, which was good enough to ensure that we would not have any stoppages as a result from dust, dirt or debris when engaging the enemy in a gunfight.
That is just my experience, but I would be willing to bet that other combat vets and grunts would attest to the same results and outcomes as I just have.
BufordTJustice
09-08-09, 11:51
it has been discussed about a million times..
one thing, however- the AK is no more reliable than a well-maintained quality AR. less so, in fact.
I take issue with this statement. A quality AR15 is very reliable when well maintained. However, a quality AK is almost ALWAYS going to be more reliable. With over 95 million in existence, your statement against AK reliability by comparing it to AR's is utterly moot. Third world countries, zero maintenance, cheap corrosive ammo, no lubrication, rampant rust.....the AK is tops for reliability. This is to it's detriment in the department of precision and accuracy, but a good AK needs to make zero excuses for its ability to operate in almost all conditions. Try running an AR COMPLETELY DRY for 5K rounds with zero cleaning either.....can't be done. MAYBE with a super high-falutin' piston gun....maybe. It's done every day with dozens of AK's in countries across the globe.
Sorry for the thread drift, but let's keep perspective here. The entire topic for this thread is about the viability of piston systems. The entire piston concept is an effort to convey AK reliability on the AR platform. I think a good piston system can and will be developed. POF & LWRC look like the best available options right now. I've held and shot both. I was pleased with both. They are not the penultimate, but they are both legitimate steps in the right direction. However, I see it all heading toward a clean-sheet design like the FN SCAR, Remington ACR, or something of that nature. I would quickly hop onto the KAC bandwagon if they developed a full-size version of the PDW dual-piston operating system for a 5.56/6.8 rifle. THAT, IMHO, could be the penultimate. I also see a caliber change coming with the platform change; 6.5 or 6.8 along w/ heavier bullets (100-140 grains) are where things are heading.
The entire piston concept is an effort to convey AK reliability on the AR platform
I refuse to believe that a piston is the deciding factor in reliability.
It's about tolerances, not pistons.
I was never a fan of piston ARs. Piston ARs seemed like a insult.
Thats said, my whole view changed after seeing the Addax ATAC style uppers. (no they are not the same as PWS, you get better shit when you get them from Addax and you can customize your order too)
The ATAC has:
Minimal carrier tilt (compared to others, plus there is a special buffer to fix that anyway if it concerns you)
Recoil of an ATAC is still not as soft as DI but much softer than other systems I have had the pleasure of playing with.
Long stroke design ( op rod is part of the BCG...looks like a ****ing AK!!)
What I like best was no knobs, no adjustments needed when using different ammo or suppressed and unsuppressed. It just shoots no adjustments needed.
So in my quest to build an SBR (11.5) and run it suppressed.....the ATAC is my choice. Hopefully, I can get it all together soon. For me it has nothing to do with clean or dirty its just what I want.
PS...No idea what happened or the story surrounding it with clear detail yet but, Saw a completely snapped in two Adams Arms op-rod the other day. Guy said it was a complete upper, Adams Arms as far as I know does not offer complete uppers......Spikes?:eek:
BufordTJustice
09-08-09, 17:21
I refuse to believe that a piston is the deciding factor in reliability.
It's about tolerances, not pistons.
I agree that just slapping a piston on an AR pattern rifle can be borderline insulting when poorly done. Many conversions fall into this category for me. They just make me cringe. I would much rather own a good mid-length upper than an el-cheapo piston deal. However, the DI system is NOT the best way to make a firearm function from the git-go. As posted, a clean-sheet redesign is needed. Just slapping a piston on what WAS a good system is not the answer... but neither is settling for a system that blows all those dirty driving gasses back into the receiver. We need something new. The AR was a fresh design. We need something equally innovative again.
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