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[ARCHIVED THREAD] - Gas Piston AR?? (Page 2 of 4)

Posted: 4/25/2009 9:47:01 AM EDT

[#1]

Piston on AR's shine in SBR, Suppressed and Full Auto applications. Their use for semi-auto guns in less strenuous applications is debatable.

Ive heard this said before.

Why would a gas piston work better than a DI gun in SBR form. Actually, the better question is how much better can it work over a qualtiy DI gun? My 10.5 inch DI gun runs like a swiss watch, with or without suppressor. The only advantage I see is parts cleaning being less difficult on a piston gun. Reliability is certainly not a factor with a quality DI gun.

Posted: 4/25/2009 9:51:05 AM EDT

[#2]

I think it is funny that these two systems wind up being debated so emotionally on this forum. The gas system of the AR is like the engine of a popular muscle car. The manufacturers of these automobiles tried several configuration changes through the years of developing these cars and you have circles prefering this config over this config. Big deal! that's exactly what it is, a preference. Get over it.

As for function. The M16/AR platform has a weakness and this weakness is it's gas system and the primary round this weapon has fired over the years. The reason why there are so many calibers available for this weapon and the Military keeps evaluating different loads and there is an alternative gas system out there is proof of this. If these weaknesses didn't exist then the market would not support these variations.

Yeas there is work to be done on the piston systems, if not the design, then the testing to prove its metal.

To simply dismiss the piston as a fad or adopt the attitude that the DI has worked for 40 some odd years and therefore why look for an improvement in the platform is just emotional insecurity in what you have invested in. There are pluses and minuses to both systems and I have both so i'm not talking about something I haven't experienced. I don't pretend to be an engineer just a fan of shooting and owning a lot of firearms. Why do we waste so much time tearing each other down in order to prop ourselves up. We should all be trying to improve the platform. In a vacuum absent of many variables the piston is a better gas system than the Direct Impingement system. If LMT or LWRC makes a system that can be retrofitted onto an existing ar then we all win. Notice I didn't mention HK because their platform is not compatible with our platform.

CANT WE ALL JUST GET ALONG...LOL just kidding but i thought it fit here.

Posted: 4/25/2009 11:00:01 AM EDT

[#3]

Quoted:

It has been well established that the dust tests may have been biased.

The "piston" guns tested were guns that the manufactures were allowed to prep before the testing.

The M4's were pulled from inventory.

Repeat testing also resulted in the M4's having less than half the number of failures vs the original testing.

I think "well established" is overselling the point a bit but I agree that the test had some problems. I am curious about your last statements. Can you point me to the results of repeat testing? I'm not saying it didn;t happen, it's just heresay until I can see the data myself.

If I want a piston operated gun I'll buy one designed from the ground up to use a piston.

That's up to you, but there are advantages to using the AR platform fro those that want a piston gun: parts commonality and platform training. My LWRC is 80%+ common with my Colt. If a part breaks, I can get a replacement from almost anyone unless it's one of the proprietary components. On a platform like the SIG, or XCR, or SCAR, if something breaks, there's only ONE source for parts. AS for training, it's transparent to me as a user between my DI Colt and Piston LWRC. I can train with either and be training for both. Not so with another platform

Not a piston shoehorned into a rifle that wasn't designed that way that may or may not have problems later in its life cycle.

AS I've demonstrated, from an engineering point of view, that's a bogus argument unless you back it up by data, and you can't. You might as well say you should use a gun designed as a carbine from the ground up instead of a rifle-length system kluged up to operate as a carbine. There were engineering problem s associated with this transition.They were overcome until satisfactory performance was achieved. But it is a FACT that the carbine gas system is harsher on the gun than a rifle-length system.... parts wear out faster. I don't see the same argument from your side suggesting we dump the M4 for a dedicated carbine design..... because it's a nonsense argument.

Also google "problems with HK416" it will be educational.

Another BS point. Google "problems with M4 carbine" and see. Any machine made by man will have failures. But you need consistent data. Internet posts don't constitute engineering data.

Do you have an AKO/DKO password?

If not then your not going to be able to look at the reports yourself.

I'd post a copy paste of the tests but it's 240 pages long and I don't have an entire day to make a short version for you as I'm currently in Iraq.

Hey Dude, just post the reference info if you have it. I can probably track it down through one or another data bases I have access to. I appreciate the tip!

You didn't think the dust test was the only test in that evaluation did you?

Of course not! I've been a Defense R&D engineer for 25 years, I know better than that!

Army Times printed the dust test due to it's "sensational" nature. The Army Times is the New York Times of military papers. And just as truth full and bias free.

If you pay attention almost every publication mentioning the dust test, is directly quoting the Army Times.

I don't bother with the Army Times. I got my info about the dusting tests directly from the Crane summary briefings and some brief discussions trying to explain why the M4 performed much worse than it had in previous tests. Even the engineers involved acknowledged there might be problems with the test protocol since the results did not appreat to be repeatable.

I'd also like to point out the DoD has an entire division dedicated to testing and evaluating small arms, even if/when there are no plans to replace current small arms. The job is to test potential advancements in small arms and submit recommendations for further testing up the DoD chain. From time to time these tests make the news. Generally when a new weapon is tested by a big company seeking a mil contract, congress gets noisy about how the m4 is suddenly a bad weapon after reading the army times, or someone feels like doing an article of why this is so much better than the M4 or why the M4 is a poor weapon.

AS I said, I am VERY familiar with the DoD RDT&E processes. I work in them every day.

Have you checked the possible bolt drag issue in your LWRC? On a few POF guns and at least one LWRC I know of the Cam Pin is marring the upper receiver when it unlocks as the bolt carrier yanks it back.

FWIW, the wear from the cam pin in my LWRC is the same as in my Colt (that is, there is a bit of wear, but nothing to be concerned about). LWRC is going to release an "enhanced" cam pin in the next few weeks to reduce this wear that can be used in their guns, or even in DI guns. I'm gonna buy a few.

Adams Arms offers a spring that slips over the bolt tail to keep it in the fully locked position until the cam pin fully cams. More info here it also alludes to some issues (ones that are sometimes found on DI but not as much) that might be exacerbated buy running piston. If I were running a piston that had that issue I'd just take the bolt carrier assembly with me to a hardware store and find a spring that works out of a parts bin.

Interesting, but I ask again... what is the failure anticipated from this? Unless it causes a problem in function, I'm not concerned. Still I may pick up one of these Adams springs and see how it affects the system.

Posted: 4/25/2009 1:42:54 PM EDT

[#4]

Just to try to cut all the debate short, my ending statement is that gas piston systems may be ideal, but only for actions that were designed from the ground up as gas piston systems. Trying to retrofit one to a DI gas system with a true straight line action is vaguely like retrofitting a carburetor to a modern car that currently has computer controlled

electronic fuel injection, or, if you prefer, retrofitting EF to a '57 Chevy. Yeah, either way it's possible to make it work but that doesn't mean that it's the BEST way to make

it work. You'll always get the best performance out of the product that was designed and executed as an entire SYSTEM.

If you want a rifle based on a gas piston system, I'd suggest buying one that was designed from the ground up for that operating system. One that's well proven, too.

I'm sure you can think of a few examples.

CJ

Posted: 4/25/2009 1:56:23 PM EDT

[#5]

My thoughts on the gas piston AR..........leave the AR as it was designed, it works fine, it is tried and true.

"If it ain't broke, don't fix it"

Posted: 4/25/2009 4:07:54 PM EDT

[#6]

Innovation is born from looking at current products, product engineering, or product
methodologies and operation, and finding ways to improve on those current products, or to develop newer and advanced products.

Posted: 4/25/2009 4:18:33 PM EDT

[#7]

Quoted:
Just to try to cut all the debate short, my ending statement is that gas piston systems may be ideal, but only for actions that were designed from the ground up as gas piston systems. Trying to retrofit one to a DI gas system with a true straight line action is vaguely like retrofitting a carburetor to a modern car that currently has computer controlled
electronic fuel injection, or, if you prefer, retrofitting EF to a '57 Chevy. Yeah, either way it's possible to make it work but that doesn't mean that it's the BEST way to make
it work. You'll always get the best performance out of the product that was designed and executed as an entire SYSTEM.

If you want a rifle based on a gas piston system, I'd suggest buying one that was designed from the ground up for that operating system. One that's well proven, too.

I'm sure you can think of a few examples.

CJ

Yeah, like fitting a carbine length gas system on an action designed to work with a rifle-length one?

Pffft.... the AR system works FINE with a well-designed piston... just like the carbine length gas system works fine with a little tweaking... though it's harder on the parts.

Posted: 4/25/2009 6:45:21 PM EDT

[#8]

None of that changes the fact that a gas piston system imposes stresses on the AR's parts in a different

way than it was designed to handle, and also substantially changes the mode of operation of the bolt, and NOT

in a way that ANYONE would think is actually an improvement. It's not necessarily worse, but it's definitely

not better.

Credit must be given: The AR design is robust enough to easily deal with the very different dynamics

of a gas piston system that it was never designed for, and that says a lot for its engineering.

CJ

Posted: 4/25/2009 8:45:04 PM EDT

[#9]

Quoted:

None of that changes the fact that a gas piston system imposes stresses on the AR's parts in a different

way than it was designed to handle, and also substantially changes the mode of operation of the bolt, and NOT

in a way that ANYONE would think is actually an improvement. It's not necessarily worse, but it's definitely

not better.

Credit must be given: The AR design is robust enough to easily deal with the very different dynamics

of a gas piston system that it was never designed for, and that says a lot for its engineering.

CJ

It also says a lot for the engineering (and not marketing) of the companies that have designed, built and successfully integrated their high quality piston systems into the AR platform.

The DI Gas System is not all bad or junk, but it too has design limitations, which is especially evident in a Carbine length configuration, for which the DI is not optimally designed for. The DI Gas System was optimally designed to operate in a rifle length configuration.

Posted: 4/26/2009 4:37:57 AM EDT

[#10]

Quoted:
None of that changes the fact that a gas piston system imposes stresses on the AR's parts in a different
way than it was designed to handle, and also substantially changes the mode of operation of the bolt, and NOT
in a way that ANYONE would think is actually an improvement. It's not necessarily worse, but it's definitely
not better.

Yes, the AR platform was not orginally designed to work with a piston. It also wasn't deisgned t work with a carbine gas system. SO WHAT? Unless the problems introduced compromise function and cannot be overcome it doesn't matter. And there ARE advantages to to a piston system.... reduced fouling in the receiver will reduce wear, as will lower operating temperatures.

Credit must be given: The AR design is robust enough to easily deal with the very different dynamics
of a gas piston system that it was never designed for, and that says a lot for its engineering.

Which is another reason some folks who want a piston gun want a piston AR... we believe int eh soundness of the platform in general.

Posted: 5/3/2009 6:53:43 AM EDT

[#11]

Strongbow,

You're on the right track. However, you're dealing with a topic that involves change and change isn't something people deal with rationally.

If you take the view of some here and this has been stated before, there would be no innovation or improvement of anything. We'd all be riding horses or sitting in model T's.

The AR has been a very successful platform. Both variants appear to be reliable and consistent in performance. While a gas system appears to have the advantage of lower heat and less gunk. Both of these features offer goodness on a rifle platform.

It is inconcievable to me that anyone would think HK, or anyone else for that matter, would design a gas piston system on the AR platform without making the necessary engineering changes to the platform.

Simple resistance to change and defending a platform that really shouldn't need defending at this point.

Posted: 5/3/2009 7:43:56 AM EDT

[#12]

My first experience came not with an AR-15 but an M-16A2. Having served in the Army from 1993 to 1997 I have spent much time with the M-16 platform. My issue weapon was a FN built M-16A2 with M203. I believe most opinions here are being expressed by young kids whos only experience with the weapon is on a local shooting range or their buddies back 40. I can tell you from actual military experience that the direct impingement gas system is NOT GI friendly. It "shits where it eats" for starters so that makes for issue #1. Try riding to the qualifying range @ Ft Sill Oklahoma @ 4 Am in the back of a 2 1/2 on a dusty ass tank trail and all that Oklahoma red dirt covers everything. You pray to god that you have time to hit the cleaning area before you step up to the line to qualify. Then after a 12-14 hour day of shooting and your weapon your pissed off cause your weapon jammed numerous times and you failed to qualify expert. You go to armor and all they say is clean it.
Dont even think of firing a DI gun with the blank firing device and blanks, my god. I would ALWAYS get killed when fitted with the laser tag equipment and blanks because the damn thing jams. I just thank god that I never had to qualify the damn thing in 29 Palms or White Sands because the DI system aint got the ass to push back a dirty bolt carrier. We would shoot in the sandbox and 2 guesses what happened. Anyone? Anyone?
It took me about 10 years to get over the hatered for the M-16. I now love the AR-15 platform but Im not some commando that his life depends on the thing. If that were the case GIVE ME THE HK 416!!!! Im down to 3 each DI AR's which run just fine after a day of recreation shooting. Larue LT-15, Colt 6921 and Knights SR-15. Oh and a M16A2 Colt Commando unfired safe queen. The others are piston guns LWRC's and LMT. My next will be the HK's when they come out later this year. PISTONS WHEN YOU LIFE DEPENDS ON IT!!!!!

Posted: 5/3/2009 7:46:30 AM EDT

[#13]

So, my question is, how did HK address the operating mode of the bolt? With the designed DI gas system, it's locked into place in full battery by forward acting gas pressure for a brief millisecond or two while gas pressure in the chamber tapers off. The bolt does begin to rotate to the unlocked position as soon as the bolt carrier starts its rearward motion, but the bolt is held in position and not allowed to ram into the locking lugs instantly. In fact, the rear faces of the bolt lug don't impact on the front faces of

the barrel extension lugs in a DI gas system, but when you simply yank the bolt and carrier back without that additional forward force on the bolt, you do get lug to lug

contact and accelerated wear, and sometimes, lug breakage. (In some cases. I would argue that proper fitting of the bolt to the barrel extension is MORE important with

a gas piston system for this reason. )

I'm not opposed to GP systems but I don't see that there's any real advantage to them. They do require you to look at the engineering and operation of the platform

carefully, as it does change some things that aren't obvious at first glance.

Sometimes people do things differently just to be different, and believe me, that's fine with me It's one of the things that makes the AR platform so attractive. If I had the budget I could build a thousand ARs and no two would be identical. That does have its appeal.

CJ

Posted: 5/3/2009 7:53:05 AM EDT

[#14]

I am thinking about gettign one, but I dont' know. I've got it narrowed down to a noveske Diplomat 7.5" or a LWRC 8" really just becasue I don't have one.

Posted: 5/3/2009 12:40:56 PM EDT

[#15]

Quoted:
So, my question is, how did HK address the operating mode of the bolt? With the designed DI gas system, it's locked into place in full battery by forward acting gas pressure for a brief millisecond or two while gas pressure in the chamber tapers off.

CJ

Why don't you write HK customer service and ask them to get your answer from one of their engineers? If that is really what you're objecting to, it is somewhat silly of you to assume they didn't engineer the rifle properly given their experience and track record in the industry and all of the testing that has been done on the 416 platform.

-I may just do it for you, not sure I care that much about it though.

Posted: 5/3/2009 3:08:47 PM EDT

[#16]

I'm not assuming anything. I'm just asking a question: How did H&K address that particular technical point with the 416?

It has a good reputation. I'm not a doubter, I'm just curious.

CJ

Posted: 5/3/2009 4:27:02 PM EDT

[#17]

Quoted:They do require you to look at the engineering and operation of the platform
carefully, as it does change some things that aren't obvious at first glance.

No they don't!!!! I don't have to look into any engineering!!!!!!!!!! That's what I paid LMT to do for me!!!

I don't know about you, but I do know that they have a whole lot more experience in producing AR platforms!!!!!!!!!!! Probably much more than 99.99999% of the people that visit this site!!!!!!!!!!!

Do you own and operate a company that is ISO 9000 certified to do business with the rest of the world, not to mention the US??? Do you have the expertise and experience of years of building AR rifles??? They spent a couple years and thousands upon thousands of rounds expended in testing. What have you done??? All I hear from you is your opinion and it's getting really tired.....your singing the same verse of the same song over and over and over and over...........

BTW, I didn't mention HK and or LWRCI or POF as those companies along with LMT have YEARS experience building and testing gas piston designs on the AR platform. Please if you have something to add other than the constant dribble............I'm tired and frustrated. It's up to the OP and is his money. We have already given him tons of information, threads, and personal experiences. To infuse this with parroting what the 'masses' (BTW, most of which have never owned or even shot a piston AR) are telling over and over again............

Posted: 5/3/2009 4:59:52 PM EDT

[#18]

Quoted:
I am thinking about gettign one, but I dont' know. I've got it narrowed down to a noveske Diplomat 7.5" or a LWRC 8" really just becasue I don't have one.

Try a PWS 7" Diablo. It is a long stroke piston system that has been supremely reliable in select fire situations. I really love it. PWS is currently working with Gemtech on a suppressor that will screw into there, can looking, flash suppressor. One of the great things about this system is the GP is a part of the BCG. The gas system is a single part verses a BCG, a spring and a one to three piece piston rod.

http://primaryweapons.com/store/pc/home.asp

Posted: 5/3/2009 7:07:00 PM EDT

[#19]

Quoted:Do you own and operate a company that is ISO 9000 certified

I might, only becasue I have absolutly no clue what that means....

Quoted:

Quoted:
I am thinking about gettign one, but I dont' know. I've got it narrowed down to a noveske Diplomat 7.5" or a LWRC 8" really just becasue I don't have one.

Try a PWS 7" Diablo. It is a long stroke piston system that has been supremely reliable in select fire situations. I really love it. PWS is currently working with Gemtech on a suppressor that will screw into there, can looking, flash suppressor. One of the great things about this system is the GP is a part of the BCG. The gas system is a single part verses a BCG, a spring and a one to three piece piston rod.

http://primaryweapons.com/store/pc/home.asp

I'll look into it, thanks for the info

Posted: 5/3/2009 7:13:09 PM EDT

[#20]

Quoted:

Quoted:They do require you to look at the engineering and operation of the platform

carefully, as it does change some things that aren't obvious at first glance.

...Massive snippage...

Boy, are you clocked up tonight or what?

Too much caffeine is really bad for you.

I echo the opinions and WELL CONSIDERED engineering evaluations of the AR platform, as stated by the ABSOLUTE authorities on the platform,

Eugene Stoner, and Reed Knight, who worked closely with Eugene Stoner for several years, and undoubtedly came to know the platform as well

as Mr. Stoner. I'd trust them before I'd even trust LMT.

You don't have any form of engineering background, do you? I'd guess you're not into analytical thought, either.

CJ

Posted: 5/4/2009 3:43:08 AM EDT

[#21]

Quoted:

Quoted:They do require you to look at the engineering and operation of the platform
carefully, as it does change some things that aren't obvious at first glance.

...Massive snippage...

Boy, are you clocked up tonight or what?

Too much caffeine is really bad for you.

I echo the opinions and WELL CONSIDERED engineering evaluations of the AR platform, as stated by the ABSOLUTE authorities on the platform,
Eugene Stoner, and Reed Knight, who worked closely with Eugene Stoner for several years, and undoubtedly came to know the platform as well
as Mr. Stoner. I'd trust them before I'd even trust LMT.

You don't have any form of engineering background, do you? I'd guess you're not into analytical thought, either.

CJ

A few answers ago I referred to someone that was talking with CJ that it was like him arguing with my 15 year old son...............I take that back. It's like talking with the fence post!!!!

Posted: 5/4/2009 5:03:30 AM EDT

[#22]

i've run a few thousand rounds through a few piston systems.

i like them. they do make cleaning a lot easier.

they stil shit, but at least they don't shit where they sleep.

a few things i've overheard about piston systems from other reasonaby knowledgeable folks:

1) piston parts can and do break with normal (semi-auto) usage.

2) carrier tilt issue ... this topic has been beaten to death here and elsewhere.

3) piston guns are murder on the fire control groups (the force of the bcg back is reportedly greater than with a DI gun). ergo, more wear and tear on items like the hammer.

as a consumer, i would just point out that it would be nice if the industry could eventually migrate to one short-stroke standard, which would be nice in terms of parts interchangeability as well as cost. of course, here in the U.S., we welcome competitition so many vendors (LWRC, POF, HK, Adams Arms, CMMG, Colt, etc.) have piston offerings now.

are they worth it? if you're curious and like to tinker, or are lazy or too busy to give the rifle a good cleaning after shooting, or if you have a shorty that doesn't work, or shoot a lot of full auto, they are worth looking at.

Posted: 5/4/2009 5:48:56 AM EDT

[#23]

Quoted:

A few answers ago I referred to someone that was talking with CJ that it was like him arguing with my 15 year old son...............I take that back. It's like talking with the fence post!!!!

A fence post? No, that's just not right.

Arguing with me when I'm right should be a lot more like yelling at a solid granite mountain. You can't budge me when I'm dead right.

CJ

Posted: 5/4/2009 6:44:23 AM EDT

[#24]

Quoted:

A few answers ago I referred to someone that was talking with CJ that it was like him arguing with my 15 year old son...............I take that back. It's like talking with the fence post!!!!

A fence post? No, that's just not right.

Arguing with me when I'm right should be a lot more like yelling at a solid granite mountain. You can't budge me when I'm dead right.

CJ

Right? Pffft... answer my questions:

What are the failures that the "problems" you've identified cause? Point me to some evidence they occur, and occur frequently enough to make the designs not viable.

I've heard you pontificate and play arm chair engineer, but without data, it's just your unsubstantiated opinion. And yes, I'd say the same thing to Reed Knight. Data is king.

Posted: 5/4/2009 6:56:39 AM EDT

[#25]

Quoted:

Quoted:

I have been looking at a gas piston ar. Are they really worth the extra price? YES!!! What are the pros and cons of them, what is the purpose of a gas system. Pros like them, Cons don't!!! Sorry, it's probably a dumb question, but im a newbie.

Since everyone else here is giving their own 'OPINION', there's mine!!! I actually have one...........LMT MRP CQB Piston. I don't have carrier tilt!!! I don't have unusual wear anywhere I can see!!!! It runs well and is more accurate than I am!!! It is definitely easy to clean and doesn't require that 'wet' look!!!!!

Anyone else that has one can speak up now!!! All the rest can keep blowing hot air (gases just like in your own DI version) for experience!!!

I am of the same opinion. Most people who bitch about gas piston AR's have zero real world experience using them. Mine runs Flawless and is more accurate than my DI guns. They are worth the money! POF P415 16 inch barrel.

Posted: 5/4/2009 7:11:24 AM EDT

[#26]

Quoted:

Quoted:
I have been looking at a gas piston ar. Are they really worth the extra price? YES!!! What are the pros and cons of them, what is the purpose of a gas system. Pros like them, Cons don't!!! Sorry, it's probably a dumb question, but im a newbie.

Since everyone else here is giving their own 'OPINION', there's mine!!! I actually have one...........LMT MRP CQB Piston. I don't have carrier tilt!!! I don't have unusual wear anywhere I can see!!!! It runs well and is more accurate than I am!!! It is definitely easy to clean and doesn't require that 'wet' look!!!!!

Anyone else that has one can speak up now!!! All the rest can keep blowing hot air (gases just like in your own DI version) for experience!!!

I am of the same opinion. Most people who bitch about gas piston AR's have zero real world experience using them. Mine runs Flawless and is more accurate than my DI guns. They are worth the money! POF P415 16 inch barrel.

Second, ppl who haven't had a lot of time behind a piston AR need to stay outta these kinda arguments!..Coming from DI AR's the LWRC M6A2 is a dream, best rifle I have ever shot or owned

.

Posted: 5/4/2009 12:04:40 PM EDT

[#27]

Quoted:

What are the failures that the "problems" you've identified cause? Point me to some evidence they occur, and occur frequently enough to make the designs not viable.

I've heard you pontificate and play arm chair engineer, but without data, it's just your unsubstantiated opinion. And yes, I'd say the same thing to Reed Knight. Data is king.

Let me get this straight...

You'd rather NOT believe the real engineering truth here, as determined by the DESIGNER of the AR platform, and as believed by his star pupil, Reed Knight?

For those whose reading comprehension isn't quite up to par, what's been said here is that the gas piston system isn't what the AR platform was designed for,

and there are some technical issues that need to be considered carefully. But nobody here...myself included...has said that gas piston systems don't work.

Clearly, they do. Maybe not perfectly all the time in every case, but they do have a pretty good track record. It says something about the integrity of

the AR platform that it accomodates the different system and still operates reliably.

Pick any ten rifle platforms at random and convert them from gas piston to direct impingement, or vice versa, as appropriate, and I'll bet that eight of them

wouldn't achieve such good relative results as does an AR with such a conversion.

While I do have my reservations regarding carrier torque and bolt delay, it's pretty evident that this is only very rarely a real world problem.

CJ

Posted: 5/4/2009 1:16:56 PM EDT

[#28]

To me what Noveske said makes sense on the round tube vs square reciever with rails. My point has always been and yes I do have a LMT CQB Piston, that at best any piston system is a comprimise, it has to e made to fit within the confines of the AR platform. Thats enough for me. I bought the CQB just to play with and see the differences. It WILL never be my go to gun.

Posted: 5/4/2009 1:45:45 PM EDT

[#29]

I seriously doubt any of the companies converting AR-15s to piston operation have any actual mechanical engineers on their staff.

Companies like Colt and KAC who DO have professional R&D engineering staff with a decent research budget do not see it as a good idea to convert the AR-15 to piston operation.

The piston AR-15 thing is not sound engineering, it is marketing, nothing more.

Posted: 5/4/2009 2:11:01 PM EDT

[#30]

Quoted:

The piston AR-15 thing is not sound engineering, it is marketing, nothing more.

Huh? I hope you're joking. I suppose you're going to stand there an try to tell me HK has no engineers on staff. Come on, why would you even post something so ridiculous?

Come back down to Earth spaceman. The thin air is space is eating at your senses.

Posted: 5/4/2009 2:13:20 PM EDT

[#31]

I am a Gas Piston Upper Builder, and I have a full time engineer for R&D, and Testing on staff.

If I come out on a public forum, and state my GPU's are this or that, I will only do it after my engineer and I have done our due diligence.

The High Quality Piston Systems are Engineering, since you have to work with all sorts of factors from timing, pressure, parts interaction, tolerances etc.

Quoted:

I seriously doubt any of the companies converting AR-15s to piston operation have any actual mechanical engineers on their staff.

Companies like Colt and KAC who DO have professional R&D engineering staff with a decent research budget do not see it as a good idea to convert the AR-15 to piston operation.

The piston AR-15 thing is not sound engineering, it is marketing, nothing more.

Posted: 5/4/2009 2:15:48 PM EDT

[#32]

There are other Piston System and Designs on the market...

It is like cars, not one car is going to be the ultimate solution for everyone on the market, and this applies to piston systems, DI rifles etc.

(BTW, I Love the Avatar.. I have restored 2 myself).

Quoted:

To me what Noveske said makes sense on the round tube vs square reciever with rails. My point has always been and yes I do have a LMT CQB Piston, that at best any piston system is a comprimise, it has to e made to fit within the confines of the AR platform. Thats enough for me. I bought the CQB just to play with and see the differences. It WILL never be my go to gun.

Posted: 5/4/2009 4:04:45 PM EDT

[#33]

ANY gas piston mod on a AR is a compromise at best, it HAS to be made to work within the ARs demensions. Same with suspensions designed as a bolt in for say, 1st and second gen Camaros, GTO's Chevelles etc. No amount of engineering can ignore that fact. When you go with a true bolt in, its really NOT the best, but it is made to function, maybe etter, most likely though its worse. I dont have the engineering to even begin to say which is good, bad or ugly on pistons systems just what I have learned from doing suspensions, comprimises suck in the long run. Now say you want to remove frame rails and extensivly modify the car, now you can make some ass kicking setups fit and work. I just dont see within the confines of the AR upper platform there is room to do that.

Thanks, its my cheaper hobby..............I think

Posted: 5/4/2009 4:04:58 PM EDT

[#34]

Quoted:

Quoted:

What are the failures that the "problems" you've identified cause? Point me to some evidence they occur, and occur frequently enough to make the designs not viable.

I've heard you pontificate and play arm chair engineer, but without data, it's just your unsubstantiated opinion. And yes, I'd say the same thing to Reed Knight. Data is king.

Let me get this straight...

You'd rather NOT believe the real engineering truth here, as determined by the DESIGNER of the AR platform, and as believed by his star pupil, Reed Knight?

Yeah, it's not like THEY have any conflict of interest, right? Gimmeafriggin'break!

Please tell me you're not actually responsible for anything technical... or tell me what it is, so I can avoid it.

For those whose reading comprehension isn't quite up to par, what's been said here is that the gas piston system isn't what the AR platform was designed for,
and there are some technical issues that need to be considered carefully. But nobody here...myself included...has said that gas piston systems don't work.
Clearly, they do. Maybe not perfectly all the time in every case, but they do have a pretty good track record. It says something about the integrity of
the AR platform that it accomodates the different system and still operates reliably.

Yes it does. It also tells me your concersn are largely unfounded.

Pick any ten rifle platforms at random and convert them from gas piston to direct impingement, or vice versa, as appropriate, and I'll bet that eight of them
wouldn't achieve such good relative results as does an AR with such a conversion.

While I do have my reservations regarding carrier torque and bolt delay, it's pretty evident that this is only very rarely a real world problem.

Thank you for admitting that. Now we can all get on with our lives!

Posted: 5/4/2009 4:16:59 PM EDT

[#35]

The piston AR-15 thing is not sound engineering, it is marketing, nothing more.

Data? Seriously... can you back that up with data, or just an opinion?

Posted: 5/4/2009 4:29:53 PM EDT

[#36]

Quoted:

Yeah, it's not like THEY have any conflict of interest, right? Gimmeafriggin'break!

Please tell me you're not actually responsible for anything technical... or tell me what it is, so I can avoid it.

Baseless ad hominem attack...check.

FYI, in my job I'm senior technician and design engineer, working in RF systems ranging from basic

point-to-point voice radio to multi-site digital trunking systems carrying voice and data, to wireless

networking at every scale from in-building to cross-state systems. Highly technical work, possibly

more technical than what you do for a living, and I achieve the design objectives given to me, often

with simpler, more robust, and cost-effective solutions than my competitors. It's good to satisfy

the customer's needs for a million dollars. It's great to satisfy his needs for 3/4 of a million.

Yes it does. It also tells me your concersn are largely unfounded.

Concerns, or OBSERVATIONS?

Truth is, I don't have a dog in this fight. My observations are purely technical in nature, and not one

person participating in this topic has even attempted to refute my statements of technical fact.

I've considered getting a GP on an AR. I still might. But I doubt that I'll convert over entirely to GP systems

as I don't believe in putting square pegs in round holes even if they might actually run together.

Thank you for admitting that. Now we can all get on with our lives!

Not until I say you can! Permission has not yet been given!

..

..

..

...

OK, NOW you can return to your life!

CJ

Posted: 5/4/2009 4:46:54 PM EDT

[#37]

Quoted:

Quoted:

Yeah, it's not like THEY have any conflict of interest, right? Gimmeafriggin'break!

Please tell me you're not actually responsible for anything technical... or tell me what it is, so I can avoid it.

Baseless ad hominem attack...check.

FYI, in my job I'm senior technician and design engineer, working in RF systems ranging from basic
point-to-point voice radio to multi-site digital trunking systems carrying voice and data, to wireless
networking at every scale from in-building to cross-state systems.

Are you a technician or an engineer? I'm not particularly worried about the RF thing. In my experience, someone with good engineering judgment has it regardless of the technical field. My concern about your judgment in this thread is that it's based on a lot of feelings and no data.

Highly technical work, possibly more technical than what you do for a living,

I don;t want to get into a credential waving contest, but I am a mechnical engineer and have worked in DoD R&D Engineering for 25 years.

and I achieve the design objectives given to me, often
with simpler, more robust, and cost-effective solutions than my competitors. It's good to satisfy
the customer's needs for a million dollars. It's great to satisfy his needs for 3/4 of a million.

Then clearly you know the difference between having a good idea and being able to back it up with data.... that's all I'm sayin'.

Like my boss always say "That's a great idea... can you show me the data!?"

Yes it does. It also tells me your concersn are largely unfounded.

Concerns, or OBSERVATIONS?

You sure seemed to voice them as concerns., but I'll accept observations. I amend my statemtn to:

"It also shows me that your obervations have not lead to any long term performance issues."

Truth is, I don't have a dog in this fight. My observations are purely technical in nature, and not one
person participating in this topic has even attempted to refute my statements of technical fact.

Yeah, I have, and it's the simplest refutation. Can you show that the design "flaws" you have observed lead to real compromise of performance? If you can, then you have a case. If you can't, then you don't.

I've considered getting a GP on an AR. I still might. But I doubt that I'll convert over entirely to GP systems

I certainly haven;t. I own 3 AR's: 2 DI and 1 GP. My main "go to" gun is a Colt LE6920, but the M6A2 runs 4.0 as well.

as I don't believe in putting square pegs in round holes even if they might actually run together.

Once again, you're letting those "feelings" get in the way. ;)

Thank you for admitting that. Now we can all get on with our lives!

Not until I say you can! Permission has not yet been given!

..
..

..

...

OK, NOW you can return to your life!

CJ

OK, that there was funny!

Posted: 5/4/2009 6:59:50 PM EDT

[#38]

The arrogance of the DI guys and their technical arguments against the gas piston system always astound me.

Posted: 5/4/2009 7:02:59 PM EDT

[#39]

so without the bickering and fighting, what's the common theory on if it's worth trying a piston in a 7inchish barreled upper?

Posted: 5/4/2009 7:06:20 PM EDT

[#40]

Quoted:

Quoted:
I have been looking at a gas piston ar. Are they really worth the extra price? YES!!! What are the pros and cons of them, what is the purpose of a gas system. Pros like them, Cons don't!!! Sorry, it's probably a dumb question, but im a newbie.

Since everyone else here is giving their own 'OPINION', there's mine!!! I actually have one...........LMT MRP CQB Piston. I don't have carrier tilt!!! I don't have unusual wear anywhere I can see!!!! It runs well and is more accurate than I am!!! It is definitely easy to clean and doesn't require that 'wet' look!!!!!

Anyone else that has one can speak up now!!! All the rest can keep blowing hot air (gases just like in your own DI version) for experience!!!

I am of the same opinion. Most people who bitch about gas piston AR's have zero real world experience using them. Mine runs Flawless and is more accurate than my DI guns. They are worth the money! POF P415 16 inch barrel.

You must have some shitty DI guns then.

Posted: 5/4/2009 10:14:22 PM EDT

[#41]

Everything in life is a compromise, but you have to weigh the
compromise vs. the benefits, and small compromises can be made in order
to achieve better results.

For example, piston systems do add a few ounces more weight to the AR,
but a few ounces of extra weight are an acceptable compromise for a
much higher level of reliability.

Simple Bolt in piston systems are the most problematic, and I have seen first hand how they can create the situation you are talking about.

I am not here to pass judgement or to say on whose system does what, but when you just bolt on parts (using your example of suspension kits) without modification to the host platform, there are always noticeable issues with the host platform and the new parts operating effectively amd efficiently, or meshing together.

Dedicated AR Piston Systems that are designed and engineered to be installed as a dedicated piston system utilizing special tooling, alignment jigs, and that are installed professionally where the parts are fitted to certain tolerances will operate much more effectively and efficiently. Hence one of the reasons why dedicated piston uppers cost more.

The PWS piston system we use started life as a retrofit system, but after working with PWS, and relaying to them our input, and comparing notes with the PWS Design and Engineering team, they made some minor updates to their system, and they have one of the best piston systems on the market. We are going to introduce a newer system with PWS very soon, that is next evolutionary step forward...

I think my Camaro's cost me so much more than my guns... I sure miss them..

Quoted:

ANY gas piston mod on a AR is a compromise at best, it HAS to be made to work within the ARs demensions. Same with suspensions designed as a bolt in for say, 1st and second gen Camaros, GTO's Chevelles etc. No amount of engineering can ignore that fact. When you go with a true bolt in, its really NOT the best, but it is made to function, maybe etter, most likely though its worse. I dont have the engineering to even begin to say which is good, bad or ugly on pistons systems just what I have learned from doing suspensions, comprimises suck in the long run. Now say you want to remove frame rails and extensivly modify the car, now you can make some ass kicking setups fit and work. I just dont see within the confines of the AR upper platform there is room to do that.

Thanks, its my cheaper hobby..............I think

Posted: 5/5/2009 4:48:02 AM EDT

[#42]

Quoted:

Quoted:

I have been looking at a gas piston ar. Are they really worth the extra price? YES!!! What are the pros and cons of them, what is the purpose of a gas system. Pros like them, Cons don't!!! Sorry, it's probably a dumb question, but im a newbie.

Since everyone else here is giving their own 'OPINION', there's mine!!! I actually have one...........LMT MRP CQB Piston. I don't have carrier tilt!!! I don't have unusual wear anywhere I can see!!!! It runs well and is more accurate than I am!!! It is definitely easy to clean and doesn't require that 'wet' look!!!!!

Anyone else that has one can speak up now!!! All the rest can keep blowing hot air (gases just like in your own DI version) for experience!!!

I am of the same opinion. Most people who bitch about gas piston AR's have zero real world experience using them. Mine runs Flawless and is more accurate than my DI guns. They are worth the money! POF P415 16 inch barrel.

You must have some shitty DI guns then.

Please qualify your statement "shitty". Obviously you're a rocket scientist and space shuttle door gunner, couch commando.

Posted: 5/5/2009 7:17:37 AM EDT

[#43]

Quoted:
The arrogance of the DI guys and their technical arguments against the gas piston system always astound me.

I swear to God when you look at these piston vs di threads you get a tiny feeling of what Christopher Columbus went through with all the di guys screaming the earth is flat.

Posted: 5/5/2009 9:50:35 AM EDT

[#44]

Quoted:

The arrogance of the DI guys and their technical arguments against the gas piston system always astound me.

So technical findings are a sign of arrogance? Wow. You must be a liberal.

Conservative: Rational thinking. Reason and logic reign supreme.

Liberal: How it "feels" is important. Reason and logic are verboten.

GP systems impose no less than two distinct conditions on the AR system that are substantial variations from its designed mode of operation.

That's a fact. That it isn't necessarily an issue in any practical application is beside the point.

There are a lot of mechanical systems that can be run with out-of spec, differently designed parts. Put oversized wheels and tires on your car

and you may find that the tires rub when going over bumps, and it may limit your steering ability. It doesn't mean the car won't go, it just

means that the variations do have effects on the system.

Posted: 5/5/2009 9:58:47 AM EDT

[#45]

Quoted:

Quoted:
I have been looking at a gas piston ar. Are they really worth the extra price? YES!!! What are the pros and cons of them, what is the purpose of a gas system. Pros like them, Cons don't!!! Sorry, it's probably a dumb question, but im a newbie.

Since everyone else here is giving their own 'OPINION', there's mine!!! I actually have one...........LMT MRP CQB Piston. I don't have carrier tilt!!! I don't have unusual wear anywhere I can see!!!! It runs well and is more accurate than I am!!! It is definitely easy to clean and doesn't require that 'wet' look!!!!!

Anyone else that has one can speak up now!!! All the rest can keep blowing hot air (gases just like in your own DI version) for experience!!!

I am of the same opinion. Most people who bitch about gas piston AR's have zero real world experience using them. Mine runs Flawless and is more accurate than my DI guns. They are worth the money! POF P415 16 inch barrel.

You must have some shitty DI guns then.

Please qualify your statement "shitty". Obviously you're a rocket scientist and space shuttle door gunner, couch commando.

You dont see pistons on competition guns, high power or percision rigs do you?

It seems you are one of those people who bought low tier ARs and had a bunch of problems with them. So you thought a piston system would fix the problem and low and behold your AR now works.

If you bought a quality AR in the first place we wouldnt be down this road.

Posted: 5/5/2009 10:22:04 AM EDT

[#46]

Jesus F'ing Christ, I cannot believe the amount of animosity this topic evokes! I also cannot understand why teh DI guys feel so damn threatened by those who have tried piston guns. Are you afraid you'll be looked upon as 2nd class citizens or something if the piston ARs prove to be worthy?

The bottom line FOR ME is that BOTH work just fine. And yes I have both. I really don't have a favorite or a GO-TO gun between my DI LMT or my Piston LMT. I would pick up either one and not blink and eye about which one is better. I just feel that they both have their place.

For ME, I bought the piston so I could use it as my SBR and maybe use it suppressed. I have a DI for my regular carbine applications and I have a DI for my precision gun. If I was going to hump a carbine around in the mountains in Afganistan for months at a time - I would probably pick the piston carbine. If I were an LEO carrying around a carbine in the trunk or in the air conditioned car - I would probably go with the DI because its slightly lighter.

Like it or not - the military IS looking at piston ARs like the HK416 because of failures with their M4s in harsh conditions. Several JSOC units that I know of are using the HK rather than the M4. Other units still prefer the M4. The point is that BOTH work. I really don't consider one better than the other - just that one has different applications and they BOTH have their pros and cons.

Final thought - IMNSHO, I think all the arguments against a properly engineered, dedicated piston AR are just BS. The tens of thousands of rounds through put LWRCs, LMTs, etc by many experts haven't seen to show the issues that the chicken little DI crowd is throwing out here. Why can't both sides just accept that BOTH systems work well and that BOTH systems have thier own strengths and weaknesses. Its up to the shooter to decide which one best fits his/her needs.

And that's all I have to say about that.....

Posted: 5/5/2009 11:05:54 AM EDT

[#47]

Quoted:

Quoted:
The arrogance of the DI guys and their technical arguments against the gas piston system always astound me.

So technical findings are a sign of arrogance? Wow. You must be a liberal.

What technical "findings?" I don;t see any "findings." I see informal analysis not backed up by any data.

Conservative: Rational thinking. Reason and logic reign supreme.

Liberal: How it "feels" is important. Reason and logic are verboten.

Careful there cowboy... that's a dangerous road. So far, what I've seen from you is all "feelings" and no data.

GP systems impose no less than two distinct conditions on the AR system that are substantial variations from its designed mode of operation.
That's a fact. That it isn't necessarily an issue in any practical application is beside the point.

<sigh> I beginning to believe you can't learn. No. It's not beside the point.

There are a lot of mechanical systems that can be run with out-of spec, differently designed parts. Put oversized wheels and tires on your car
and you may find that the tires rub when going over bumps, and it may limit your steering ability. It doesn't mean the car won't go, it just
means that the variations do have effects on the system.

And I repeat, the AR-15 wasn't DESIGNED to operate with a carbine length gas system. And doing so indiputably increases parts wear. Is it necessarily a problem? Not with proper maintenance. Unless you can provide more than that, I think your argument is effectively countered.

Posted: 5/5/2009 11:45:41 AM EDT

[#48]

I agree with what you said.

Unfortunately a few of the DI AR advocates can't and / or won't look at change in any way since they feel the DI AR is the best set up/design for the past 40+ years, and it does not need any improvement.

The DI is a good gas system design, but it has reached its limits in the AR Carbine configuration, and it has certain limitations that some people do not want to deal with.

Therefore a High Quality, Well Designed Piston Driven AR's/Uppers provides the best alternative while staying within the AR platform.

Jesus F'ing Christ, I cannot believe the amount of animosity this topic evokes! I also cannot understand why teh DI guys feel so damn threatened by those who have tried piston guns. Are you afraid you'll be looked upon as 2nd class citizens or something if the piston ARs prove to be worthy?

The bottom line FOR ME is that BOTH work just fine. And yes I have both. I really don't have a favorite or a GO-TO gun between my DI LMT or my Piston LMT. I would pick up either one and not blink and eye about which one is better. I just feel that they both have their place.

For ME, I bought the piston so I could use it as my SBR and maybe use it suppressed. I have a DI for my regular carbine applications and I have a DI for my precision gun. If I was going to hump a carbine around in the mountains in Afganistan for months at a time - I would probably pick the piston carbine. If I were an LEO carrying around a carbine in the trunk or in the air conditioned car - I would probably go with the DI because its slightly lighter.

Like it or not - the military IS looking at piston ARs like the HK416 because of failures with their M4s in harsh conditions. Several JSOC units that I know of are using the HK rather than the M4. Other units still prefer the M4. The point is that BOTH work. I really don't consider one better than the other - just that one has different applications and they BOTH have their pros and cons.

Final thought - IMNSHO, I think all the arguments against a properly engineered, dedicated piston AR are just BS. The tens of thousands of rounds through put LWRCs, LMTs, etc by many experts haven't seen to show the issues that the chicken little DI crowd is throwing out here. Why can't both sides just accept that BOTH systems work well and that BOTH systems have thier own strengths and weaknesses. Its up to the shooter to decide which one best fits his/her needs.

And that's all I have to say about that.....

Posted: 5/5/2009 12:02:01 PM EDT

[#49]

Quoted:

a few ounces of extra weight are an acceptable compromise for amuch higher level of reliability.

This is the problem. Gas pistons do not improve reliability over DI and are actually putting more load on the bolt (a known failure point) during the firing cycle. "Heat" and "fouling" do not kill bolts, fatigue does. Has your engineer done any fatigue calculations based upon the new bolt unlocking conditions?

I love the high def video you made showing the DI gun double feed, while your gun runs fine. video

Does you or your engineer know that double feeds are caused by bad mags or improper feed ramps?

Double feeds have nothing whatsoever to do with the operating system. Nothing.

Was that included in the video out of ignorance of what causes double feeds, or are you are selling a product using misleading marketing tactics?

Posted: 5/5/2009 12:26:53 PM EDT

[#50]

Agreed, people with little no piston conversion experience probably shouldn't knock piston conversions.

People who haven't read and understood United States Patent 2951424 probably shouldn't knock the original engineering until they do so

And please don't try to tell me a company is engineering driven just because they have engineers on the payroll. Marketing types and bean counters drive engineering all the time. Unfortunately, good marketing can and often does beat good product.

[ARCHIVED THREAD] - Gas Piston AR?? (Page 2 of 4)

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