AR 15 -Piston or no piston

Discussion in 'Large-Bore/Small-Bore Rifle/Shotgun' started by bolichek, Apr 3, 2011.

  1. bolichek

    bolichek New Member

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    I'm considering buying an AR type rifle. What are the pro &cons of having a gas piston rifle or no gas piston rifle. I appreciate any responses, thanks.
  2. jbmid1

    jbmid1 Active Member

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    The standard AR's (non-piston) exhaust a lot of residue from the charge gasses directly into the action. Gas tube is pretty small and will clog also if you fire too many rounds without cleaning. But with clean burning ammo, and chrome bolt carrier pieces you may not have a problem.
  3. polishshooter

    polishshooter Active Member

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    There are many excellent piston AR designs out there but keep in mind they haven't been in service as long or as hard as the original gas impingement designs so problems are being uncovered such as binding bolts that will have to be worked out.

    The direct Gas Impingement system is what the rifle was intended to operate with, and the bolt and carrier is pushed back by gas operating with properties similar to a fluid; the original design was NOT made to open with a directed push by a rod of some type at a fixed angle and force, so a whole 'nother bunch of engineering issues come to light.

    Personally, even though we know the problems with dumping all that gas and heat and crud in the chamber/bolt area with the direct method, I have a real problem with messing with the essential original design of any firearm with the proven track record of the AR 15. What the direct system GIVES you is a much simpler and lighter design, with a lot less moving parts that can break, etc. Plus while it may NEED cleaning more, the original AR design is probably the EASIEST service rifle ever made to clean!

    Get a chrome bore and chamber and keep it clean and you will have no problems.

    The other thing to me nobody considers is that all the gas and heat and crud still goes SOMEWHERE, in the case of a piston design it goes to the piston system....which may be HARDER to clean and will cause malfunctions eventually too if NOT cleaned...so you just move the poison somewhere else, not eliminate it.

    Now piston owners will be sure to jump all over me, ;)and like I said there ARE some great new designs out there, as well as some original non-AR designs from FN, etc. that are fine weapons.


    But to me messing with the original Armalite direct gas impingement system on an AR and turning it into a piston operated rifle would be like somebody taking a JM Browning 1911 and eliminating the toggle link lock up system and making it into a straight blow back design....changing it's "essence."


    Love it or hate it, the direct gas impingement M-16 (and it's variants) is the longest issued/serving rifle in US Military History. It HAS a track record, granted not without controversy, but it has proven itself time and time again.
    Last edited: Apr 3, 2011
  4. johnboat

    johnboat New Member

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    i would buy the piston over the d.i. every day they have been around plenty long enough and have been "proven" in many real world life and death conflicts.
  5. Zhurh

    Zhurh Active Member

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    I have 556 stags, both types; see no difference in accuracy and haven't had any problems yet. My problem is ever since I got the 6.8 stag; none of my 556's ever come outta the gun safe. I think LWRC makes a 6.8 in both styles, but she ain't no 900 bucks either.

    I pick up a 338 fed AR-10 Armalite at gun shop nx saturday; can't wait to see that girl.
  6. polishshooter

    polishshooter Active Member

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    Yeah Johnboat, I agree right up to the point you consider the sheer number of rounds that have been put through both since 1960 or so, hundreds of millions or more, possibly billions worldwide through millions of M16s that arm many armies in every environment through the original design with mostly everyday soldiers, vs maybe hundreds of thousands if that much through the piston ones in the hands of relatively few "special operators."

    THAT is the "track record" that is tough to argue with.
  7. polishshooter

    polishshooter Active Member

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    But then again, I am probably biased....I'm not sure I am ready to move up to a "New Fangled" Model 12 yet because Browning's Winchester '97 still does so well for me....:p

    My handgun of choice was designed 100 years ago....


    And I didn't feel comfortable buying my first AR-15 until the design was at LEAST 40 or 50 years old....;):D:D:D
    Last edited: Apr 4, 2011
  8. LDBennett

    LDBennett Active Member

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    This is a bit off the exact subject but in a recent TV show of "Sons of Guns" they had a task of converting a AR-15 to full auto as part of a boat mounted twin AR setup. As an initial test after the conversion to full auto they ran a couple of 30 round mags quickly and consecutively through the converted full auto AR on full auto.

    The gas tube was glowing cherry red! They monitored the temp and it was in the 700 degree range. They had to water cool the guns with a copper tube coiled around the barrel using a water reservoir and a pump (no details were made available except a shot of the finished cooling system).

    How this pertains to this thread is there is a lot of heat that the gas tube dumps back into the action. While I kind of agree with the concept that the gun was designed to be gas impingement operated and probably should not be changed from that, this episode made it clear that the gas temps are really pretty high and that feeding the gas back into the action might deserve further investigation.

    The fact is very few of us will operate the gun in this fashion (full auto for 60 rounds virtually consecutively). My AR is a semi-auto gas gun and works just fine. I clean it after every range session (thoroughly) where I shoot no more than 100 rounds at a sitting and have had no signs of excessive burned powder buildup.

    Didn't we learn in Vietnam that regular cleaning (cleanliness) was next to godliness with this gun?

    I don't follow all the latest military tactical guns but I thought the latest short barreled version with all the electronic sights and other gadgets hanging off the barrel was a piston operated gun. If so, how is this gun different from the AR-15's converted to piston operation?

    LDBennett
  9. polishshooter

    polishshooter Active Member

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    LD, my son is in armor, where they all get issued M4a1s, and he trained on a straight M4 and they are still all gas.
  10. LDBennett

    LDBennett Active Member

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    polishshooter:

    Thanks, I did not know one way or the other.

    LDBennett
  11. gdmoody

    gdmoody Moderator Supporting Member

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    I have one of each, both of them Bushmasters. I really can't tell any difference in anything except the piston one is easier to clean.

    There is a very good article in this months Guns & Ammo about this. The author put several piston system ARs and two D. I. system ARs through a "torture" test. All of them were tested with dirt shoveled into the chamber area and then again with sand. He then used a degreaser of some sort to get all of the oil out of the piston ARs and ran them while dry. He put sand into the piston area then dumped them into greasy water. He did things that no normal person would ever think about. The bottom line is that the only ones that did not fail the "torture" test were the two D. I. ARs.
  12. GunHugger

    GunHugger Well-Known Member

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    A piston AR is a solution to a problem that doesn't exist.
  13. fritz

    fritz New Member

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    +1, Exactly!!!! Just another gimick to sell more guns to people that dont know any better. Modern AR's with a chromed bore and chamber does not have the problems tha exsited back in Nam when the M16 was introduced. Stoners's original design incorperated a chrome bore, chamber and bolt carrier, but our government brass decided it wasnt needed, the results were desasterous. I have had several AR's over the years and have never had problems with it being dirty and jamming. My Bushmaster Varmiter that I posted pictures of on the thread "Are AR's Accurate" Shoots one hole groups all day long and I have not taken it down and cleaned it in over a year, All I have done with it is run a bore snake down it after every shooting session. I have never had any kind of malfunctions of any kind! And as you can tell by the pics. I posted it shoots extremely well. What more could you ask for?
  14. JLA

    JLA Well-Known Member

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    I too agree... If you clean your weapon once in a while you will never have a problem... The piston ARs were a way for gougers to drive costs even further up for something extra that really wasnt any gain...
  15. DGG!

    DGG! New Member

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    I vote no-bolt!

    If you don't like to clean a rifle then don't buy any semi-auto. The gas they all use to cycle the round has to go somewhere and you will eventually have to clean it. If that is an issue then get yourself a nice Remington 700
  16. Boris

    Boris Former Guest

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    If you like the piston ARs then Google carrier tilt wear. The DGI pushes the bolt straight back. The Piston designs put alot of force on the top of the bolt that causes it to tilt down violently upon cycling. Even improved designs that address the issue will have a problem at some time.

    I think its a stupid idea. Yeah thats just my opinion. A gas piston driven AR is like converting an AK to a DGI gun. Neither makes any sense at all.
  17. Counsel

    Counsel New Member

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    I guess you are all driving the Model T bevause "it works..."

    Adcor has addressed the "carrier tilt" issue-or so they claim... If ct is a problem, then so to is di...

    To each their own-you don't need to piss
    on anything you don't own to justify your choice.

    there are good examples of each-shoot both and get what works for you and what you enjoy... Good luck and let us know the outcome! :)
  18. Boris

    Boris Former Guest

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    Tisk tisk. You didn't google did you..

    A DGI gun, because of the way it functions by design is unlocked by gas pressure. Stone designed it to unlock straight back. The piston driven guns tap a piece of steel on top of the carrier. When the top of the piston has all that force put on it it tilts the back of the carrier down. thats why its called carrier tilt wear.

    No DGI gun will ever have carrier tilt wear. Piston guns will at some time down the line have it. The gun design just does not work very well with the bolt carrier digging into the buffer tube. Yep yep, some designs are better than others and will last longer before it happens, but it will happen no matter who makes it or how much they claim they fixed the problem.

    Didn't piss on anything kiddo. I keep a long stroke piston driven Galil for my house gun so I aint worried any two ways about it. FWIW though, I have fired piton ARs and fired more than enough DGI guns. I notice a slightly higher recoil impulse. My guess ( a pretty good one at that too) is the extra weight of heavy pitons banging about increases recoil 'feel'.

    Them things are best left to the glossy pages of rags trying to sell the latest greatest gizmo........
  19. ole gobbler

    ole gobbler New Member

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    ar 15 problem

    Hello, I have a Colt Target Match hbar AR. I put a new after market upper on and I have a chambered live round in it and hbar will not pull back to eject. Should I force it back. NEED HELP! CT
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