2aHawaii
General Topics => General Discussion => Topic started by: DonRow on January 06, 2012, 01:19:46 PM
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What's your choice, and comments??
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I don't own an AR but my wife has a Sig Sauer 516, which is a piston driven type AR platform.. I'm not an "AR-ologist" but I'll take a crack at it..
People say that if you are rapid firing a piston driven AR, it's harder to stay on target because of the action of the piston...
People also say that it's a lot cleaner due to the gas only hitting the piston versus going back into the reciever with a DI platform...
People say that DI rifles are lighter in weight and have less moving parts to go wrong...
I bought the Sig 516 before transferring it to my wife because I don't like to clean so much....and my friends have AR's ;D
Please don't get offended if my input is off the mark.. I'm an AK guy and I typed just what I've heard from my AR friends... :thumbsup:
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No,no, no offense I'm picking people's brains here. :D
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Apparently military tests suggest that the piston system is the recommended way to go. The reason we haven't implemented it is the cost of refitting our arsenal of M4's.
That said, military priorities don't necessarily line up with civilian owners' priorities. Tack driving accuracy, for example, is probably not needed by military standards and they are including full auto machines in the testing.
My personal opinion, having never owned a gas operated firearm, would be in favor of the piston system. It may have a few more moving parts to go wrong, but its generally fouling that is most likely to cause something to go wrong in the first place. The idea of blowing crap into the receiver seems so counter intuitive to me - at least in terms of firearm longevity, ease of care in the field, etc. It is one of the reasons I never seriously considered buying an AR platform rifle even though I do know they are an excellent design. Field testing since the early days of Vietnam, however, seems to bear out that the AR is a surprisingly resilient field weapon regardless. They do need frequent cleaning, though, and mostly because of the DI gas - from what I understand.
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The one thing I don't understand is why the military didn't switch from 5.56 to 6.8 SPC. I mean they did the test and were impressed by the stoping power that the 6.8 produced over the 5.56. Must be more politics then anything else. :) oops sorry off topic.
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The one thing I don't understand is why the military didn't switch from 5.56 to 6.8 SPC. I mean they did the test and were impressed by the stoping power that the 6.8 produced over the 5.56. Must be more politics then anything else. :) oops sorry off topic.
I would love it if they switched to 6.8 SPC. I've been looking at that caliber, but am still on the edge with the pricey ammo.
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The one thing I don't understand is why the military didn't switch from 5.56 to 6.8 SPC. I mean they did the test and were impressed by the stoping power that the 6.8 produced over the 5.56. Must be more politics then anything else. :) oops sorry off topic.
I would love it if they switched to 6.8 SPC. I've been looking at that caliber, but am still on the edge with the pricey ammo.
Oh great round I took out three pigs already with mine @ 2-300 yards. I can get them from a guy who does reloads here for $20 for 25 rounds.
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Switching away from a NATO round - especially mid-stream as we are over in the Sandbox - is no light matter. There is also the expense of switching over the entire arsenal or... replacing it. Pricey.
Though I agree. 5.56 is another reason I never looked seriously at an AR.
Of course, what I own are .44's and 45's - I'm a big bore guy so my idea of a rifle round (again, civilian, not military) is the .308. PTR-91 is what I was thinking were I to go the Big Black Rifle Route.
Which (uh, right, what was the topic again?) is recoil operated - thus avoiding the DI vs. piston thing. Oh - and the price is also the reason we haven't switched the M4's over to pistons, same as 6.8 SPC.
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i have a DPMS gas AR.. cause it was cheaper than piston!
but if you guys are in to bigger cal... check this out
http://300aacblackout.com/
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My take:
DI:
Proven platform. Yes it is dirtier than a piston, but the weight can be significantly less. With regards to function, unless you are running a very short gas system it's not a big deal. Carbon fouling.......unless you are dumping a crapload of ammo at one time it's not going to be an issue (see military engagements rather than what we see as civilians, even in classes/competition). Yes it's dirtier and a pain in the butt to clean, but no it should not affect function.
Pistons:
Cleaner than a DI system. The internals will be cooler and cleaning will be much easier. Piston affecting rifle........I think this is more along the lines of the shooter rather than the system. There are other systems that use pistons where this doesn't come up. Heat - I tell you what I was shooting my piston and if I wasn't wearing gloves I would have had a carbon streak on my burnt thumb.
Both have their places. Like all things firearms, there are tradeoffs with both.
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I previously owned a Bushmaster CAR-15, was issued a M-4, have a LMT MRP GP AR. Personally, I like how clean the GP stays esp in the receiver area. It is not spotless clean since you still get fouling when the bolt unlocks and ejects a spent brass and there is carbon foiling from propellant at the gas to piston interface. TheDI gun gets carbon fouling from the propellant in the chamber area which I am not too keen on even though the Stoner weapon system has been around for awhile. Never had to fire the issue M-4 for protection (nor was that I mission) while in Iraq though just on the range firing and carrying/storing I never did have a weapon malfunction as long as it was lubed up properly. I also kept a spare bottle of lube on my armor just to drop in the chamber area if need be. If I had to do it all over again, I think I would buy a Troy arms M7 upper kit and a lower or else a Daniel Defense Rifle since both are lightweight rifles. I do not see much of a difference from GP to DI in terms of accuracy or reliability.
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gas, because I have never experienced a failure due to the gas system.
Less moving parts
More common
Cleaning is not that big of a deal, even after shooting a lot.
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I've heard that accuracy suffers in a piston system, all other things being equal. (Which of course they never are... but anyway) If I remember right, the GP systems need a bigger gas port in order to tap off enough gas to get the piston moving, which causes the barrel to whip more than the smaller port on the DI system. I couldn't find the video I saw, but it was a high-speed camera shot of an AR and an AK firing, and the barrel snap on the AK was pretty jaw-dropping. Still happened to the AR when the bullet passed the gas port, but not nearly as badly. That's my coupla pennies, anyway.
Personally, I'd feel better about a DI AR, simply because it's been around longer and in larger numbers than their GP stepchildren.
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Gas impingement all the way, Im selling my only piston AR (LWRC) to buy another KAC direct impingement rifle (Block III SBR). Ive got 5 ARs already from 10.3" to 20", I see no reason to go to something else when mine work so great. Im even second guessing registering my SCAR as a SBR, Id like to have been able to recoup the cost and sell it but its harder to push as a title II firearm with my name engraved on the side.
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As far as reliability after 1000 rounds. The piston system will be cleaner. The gas system will need to be cleaned. So as far as I am concerned I dont think I will ever get that far unless I am in combat or something. As far as what I am doing now I see no need for the extra expense of a piston system. Especially shooting semi-auto. The Piston system will need to be serviced sometime down the road with new parts. extra expense. little gain.
BUT if I was going to war.....and get to use full auto......thats another story. (thinking about it I would still go pistonless)
I have to research about the added kick from the piston. Right now I have a compensator my friend designed and my gun doesnt move at all (5.56) I wonder how
it would react on a Piston system. interesting.
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As far as reliability after 1000 rounds. The piston system will be cleaner. The gas system will need to be cleaned. So as far as I am concerned I dont think I will ever get that far unless I am in combat or something. As far as what I am doing now I see no need for the extra expense of a piston system. Especially shooting semi-auto. The Piston system will need to be serviced sometime down the road with new parts. extra expense. little gain.
BUT if I was going to war.....and get to use full auto......thats another story. (thinking about it I would still go pistonless)
I have to research about the added kick from the piston. Right now I have a compensator my friend designed and my gun doesnt move at all (5.56) I wonder how
it would react on a Piston system. interesting.
well, i can tell you that i have shot a 1000 rounds plus and my ar kept going, needed some lube on the bcg, but thats it. That was split up between several shoots without cleaning. These were reloads, and i have found they are cleaner than factory crapolah.
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A thousand rounds without a break for cleaning sounds like a hell of a firefight to me, even by military standards, although I could be wrong about that. That's 33 magazines' worth of ammo, plus some change. I'm thinking you'll have either won the fight or been killed by the time you spend that much ammo. If there's been over a thousand rounds downrange with no winner, I'm going to propose we call it a draw and everybody go home! lol (Long story short, 1k sounds plenty good to me!)
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A thousand rounds without a break for cleaning sounds like a hell of a firefight to me, even by military standards, although I could be wrong about that. That's 33 magazines' worth of ammo, plus some change. I'm thinking you'll have either won the fight or been killed by the time you spend that much ammo. If there's been over a thousand rounds downrange with no winner, I'm going to propose we call it a draw and everybody go home! lol (Long story short, 1k sounds plenty good to me!)
nope, its was range time followed by two hdf shoots...but i know my Daniel Defense M4 can handle it...:)
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http://www.ar15.com/content/page.html?id=535 (http://www.ar15.com/content/page.html?id=535)
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Depends on what piston system, as some are inferior then the others. I am big fan of the LWRC rifles.. Lifetime warranty as well.
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A thousand rounds without a break for cleaning sounds like a hell of a firefight to me, even by military standards, although I could be wrong about that. That's 33 magazines' worth of ammo, plus some change. I'm thinking you'll have either won the fight or been killed by the time you spend that much ammo. If there's been over a thousand rounds downrange with no winner, I'm going to propose we call it a draw and everybody go home! lol (Long story short, 1k sounds plenty good to me!)
nope, its was range time followed by two hdf shoots...but i know my Daniel Defense M4 can handle it...:)
I didn't word that very well. I meant to illustrate that your 1000-round "torture test" far exceeds the actual round count without an opportunity for a quick and dirty field strip/clean that a body would ever reasonably (or even unreasonably) expect to see, even in an end-of-the-world-as-we-know-it scenario. Which is why I'm perfectly comfortable going with DI.
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I've shot both DI and GP. I own a a gas piston one. The first DI's I shot were military issue one back when I was in highschool and went to JROTC spring camp up here at Schfield. Got to shoot them on semi and 3-round burst. I loved those rifles. Later I shot my friends Stag Arms and Colt AR's and again solid rifles. So why did I buy a gas piston? Mostly because that is what fit my girlfriend the best. I bought a PWS MK116. I listened to Tony's (Gun Source) spiel about DI vs GP. He pushes PWS big time, but I wasn't sold right off the back. I spent a lot of time reading and then brought my girlfriend down to see the rifle. She loved it. I like because of the ease of cleaning and it is just as accurate as my friends DI rifles if not more so. The best part of the gas system is the lessened felt recoil. My gas piston is a solid performer with very little recoil, it kicks like a .22. The other consideration is looking at what SpecOps guys are using. Reports state that SEAL Team 6 used gas piston HK416 in their raid on Osama's compound. But which is better for SHTF time it would be the DI. Less moving parts and easier to maintain and repair if need be.
This a link to the snipershide forum which help me to decide if a gas piston PWS was something worth considering.
http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2202139 (http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2202139)
HK propaganda showing why gas piston is better than direct impingement.
http://youtu.be/vjMH94PuT_I (http://youtu.be/vjMH94PuT_I)
Overall I think it boils down to what you want. My 6.5 Grendel rifle I'm building is DI and I have no problem with that.
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A thousand rounds without a break for cleaning sounds like a hell of a firefight to me, even by military standards, although I could be wrong about that. That's 33 magazines' worth of ammo, plus some change. I'm thinking you'll have either won the fight or been killed by the time you spend that much ammo. If there's been over a thousand rounds downrange with no winner, I'm going to propose we call it a draw and everybody go home! lol (Long story short, 1k sounds plenty good to me!)
nope, its was range time followed by two hdf shoots...but i know my Daniel Defense M4 can handle it...:)
I didn't word that very well. I meant to illustrate that your 1000-round "torture test" far exceeds the actual round count without an opportunity for a quick and dirty field strip/clean that a body would ever reasonably (or even unreasonably) expect to see, even in an end-of-the-world-as-we-know-it scenario. Which is why I'm perfectly comfortable going with DI.
Back last year, 3 of us were at SRGC. My friend brought his LWRC rifle. He ended up putting some 800 rounds through his gun. Total time was a bit less than 4 hours. It was a rifle & magazine break in-test. All semi auto.........and yes the rifle was cooking. No issues with the LWRC. No cleaning. It worked. That said, I'm quite sure if he had a good quality DI gun, it would have been fine also. There was a Youtube vid some guy had posted when this issue came up about AK vs AR reliability. Anyhow the vid shows 30 round mag dump after 30 round mag dump on full auto until the AR's furniture caught on fire. It was crazy. Anyhow if I ever come across the vid again I'll post it.
I've shot both DI and GP. I own a a gas piston one. The first DI's I shot were military issue one back when I was in highschool and went to JROTC spring camp up here at Schfield. Got to shoot them on semi and 3-round burst. I loved those rifles. Later I shot my friends Stag Arms and Colt AR's and again solid rifles. So why did I buy a gas piston? Mostly because that is what fit my girlfriend the best. I bought a PWS MK116. I listened to Tony's (Gun Source) spiel about DI vs GP. He pushes PWS big time, but I wasn't sold right off the back. I spent a lot of time reading and then brought my girlfriend down to see the rifle. She loved it. I like because of the ease of cleaning and it is just as accurate as my friends DI rifles if not more so. The best part of the gas system is the lessened felt recoil. ..................
I like the weight on the PWS. If it isn't the lightest piston out there, it has to be close. What I don't like is the way the op rod is captured on the bolt carrier. It's so light I'm afraid that I would accidentally bend that rod when I was cleaning the rifle.
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I like the weight on the PWS. If it isn't the lightest piston out there, it has to be close. What I don't like is the way the op rod is captured on the bolt carrier. It's so light I'm afraid that I would accidentally bend that rod when I was cleaning the rifle.
I'm 110% with you on both points. The weight of the rifle inlcuding holosight is even easy for my rather petite gf to shoulder and fire comfortably. In fact she loves shooting it. And yes that whole assembly thing is funky. The first time I cleaned it on my own it took me almost half in hour to get the charging handle bolt carrier group back in. :( Since then I've gotten used to it.
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I find it strange that so many people are citing weight as a disadvantage to the piston. The gas chamber is smaller than for DI, so there's a weight savings there, and the pistons themselves are pretty darned light. It can't be a difference of more than a couple of grams!
As far as reliability, I think there are plenty of examples out there showing pretty conclusively that both systems are capable of extended continuous operation in less-than-ideal circumstances.
As far as accuracy, I'm just not buying that there's much difference. Slo-mo images showing one barrel whipping more than another probably have more to do with the specific barrel than the size of the gas tap.
As far as recoil, it seem to me that the piston system, having more mass to be moved, would eat up kinetic energy that a DI system would turn into recoil. However, given my earlier comment about the light weight of the pistons, it would probably be a negligible gain.
Cleaning? Sure you have more tube to clean on a DI, but cleaning the seared-on crud from a gas piston ain't no picnic.
In short, as far as I can tell, the only reason to prefer one system to another is that you've chosen to do so! :)
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I find it strange that so many people are citing weight as a disadvantage to the piston. The gas chamber is smaller than for DI, so there's a weight savings there, and the pistons themselves are pretty darned light. It can't be a difference of more than a couple of grams!
As far as reliability, I think there are plenty of examples out there showing pretty conclusively that both systems are capable of extended continuous operation in less-than-ideal circumstances.
As far as accuracy, I'm just not buying that there's much difference. Slo-mo images showing one barrel whipping more than another probably have more to do with the specific barrel than the size of the gas tap.
As far as recoil, it seem to me that the piston system, having more mass to be moved, would eat up kinetic energy that a DI system would turn into recoil. However, given my earlier comment about the light weight of the pistons, it would probably be a negligible gain.
Cleaning? Sure you have more tube to clean on a DI, but cleaning the seared-on crud from a gas piston ain't no picnic.
In short, as far as I can tell, the only reason to prefer one system to another is that you've chosen to do so! :)
Yeah Yeah, what Tom_G said ;D
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There is already a piston in the DI design.
How about a shoot out?? DI vs. gas piston" rifle at the 600 yard line. Jan 27or 28at Puuloa Range.
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There is already a piston in the DI design
Well, technically, sure. And there are two pistons in the piston design!
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OK guys, here's the vid:
Colt M4/AR-15 Fired Full Auto untill it catches on fire (http://www.youtube.com/watch?v=Kzfm4pYhIyY#)
Lost count of the mags, but you're getting up near 30 30RND mag dumps before the gas tube is history.
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Daaaaammmmmnnnn!! That's pretty funny and sad at the same time.
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Anybody have a pigtail gas tube?
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Daaaaammmmmnnnn!! That's pretty funny and sad at the same time.
Wish I had a budget for ammo like that guy...........
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Daaaaammmmmnnnn!! That's pretty funny and sad at the same time.
Wish I had a budget for ammo like that guy...........
Wish I had that guy's whole gun budget! Gas tube---effed. Barrel---effed. Everything else---maybe effed. :( Cool demonstration, though. Reposted to my facebook for all the AR naysayers.
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Daaaaammmmmnnnn!! That's pretty funny and sad at the same time.
Wish I had a budget for ammo like that guy...........
Wish I had that guy's whole gun budget! Gas tube---effed. Barrel---effed. Everything else---maybe effed. :( Cool demonstration, though. Reposted to my facebook for all the AR naysayers.
So long as the NFA parts are OK, it's a (relatively) cheap repair job.
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There is already a piston in the DI design.
How about a shoot out?? DI vs. gas piston" rifle at the 600 yard line. Jan 27or 28at Puuloa Range.
The next Puuloa Club shoot is 21-22 Jan. I don't think you'll get any takers from Team Gas Piston. National Match style shooting is too strenuous for most folks.
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ohhh 600 yards. Reach out and touch someone!
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Puuloa Rifle and Pistol Club had their annual membership meeting. By popular vote, the next practice match is moved to 28-29 Jan. Team Gas Piston has another week to figure out if they will be able to hit paper at 600 yards.
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For SRGC members looks like KR-3 will be available near the end of January. Long long range. No paper either, but it's an interesting venue to shoot at. Very humbling.
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Cool, I figured someone asked this here already. Thinking of picking up an AR so this will help me pick which.
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Cool, I figured someone asked this here already. Thinking of picking up an AR so this will help me pick which.
So you're gonna pick up both? ;D The question is which first.... :rofl: I'm a AK guy, so my first was a piston driven AR... I don't have it any more but I think I'm gonna renew my permit tomorrow and build a DI sometime in the near future in coyote tan..... Dexter keeps pressuring me and I'm ok with it.... :rofl:
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So you're gonna pick up both? ;D The question is which first.... :rofl: I'm a AK guy, so my first was a piston driven AR... I don't have it any more but I think I'm gonna renew my permit tomorrow and build a DI sometime in the near future in coyote tan..... Dexter keeps pressuring me and I'm ok with it.... :rofl:
hahaha we got the Tan special coming in next week....all FDE AR15...we can convert it to Piston and 762x39 also!
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I'm leaning DI too, we'll see...