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OutdoorPursuitsCanada
04-22-2012, 12:31 AM
Did a search and haven't found anyone open up this can of worms yet so I thought I might as well be the first....
What are all ya'lls thoughts? Direct Impingement or Gas Piston in an AR style "black" rifle - and this is taking everything into account: cost/value, reliability, feeding, extraction, maintenance, accuracy, etc... lets just open this thread right up!

Ar180shooter
04-22-2012, 06:21 AM
IMO a solution looking for a problem.

There are some sweet piston AR's out there though... but they're not sweet because they're piston AR's... they're sweet because they're well made rifles, and would be just as good in a DI configuration.

All IMO at least.

Diesel
04-22-2012, 06:26 AM
I have both, what it boils down to for me is this. The piston AR is much easier to clean and keep clean....and I like that.

I would buy another piston AR without a second thought.

RobSmith
04-22-2012, 09:23 AM
Some of the early factory piston-AR's as well as early "conversion kits" were said to have problems with busted off gas keys and chewed up uppers and such. The newer offerings are said to be GTG though. Runs cooler and cleaner, at the cost of a bit of weight and complexity, possibly mild loss in accuracy.

50calshooter
04-22-2012, 08:37 PM
A couple points...

I have no problems with a factory produced piston AR, I do have problems with piston conversion kits. To me it's a solution to a problem that doesn't exist.

I don't buy into the it "runs cleaner" theory. The fact is, all guns need to be regularly cleaned and maintained, if done right, there should be no issues of excessive carbon build up. Clean often, clean properly.

A well maintained DI gun is just as reliable and accurate as the rest, it will stand the test of time and IMO, less moving parts is a good thing.

The original AR was not designed to be used as a piston platform, it's a gas gun period. Don't question Eugene,



That's all I got...

50calshooter
05-15-2012, 11:24 AM
Seriously, how was this debate put to sleep in less then one page.... lol I expected a few pages of honest debate....

OutdoorPursuitsCanada
05-15-2012, 12:00 PM
Thats what I was hoping for - nobody seemed to bite though.

Onagoth
05-15-2012, 12:48 PM
I don't fully understand how piston works or what its benefits are...so I don't have a dog in the fight.

I've only ever owner DI guns.

H2O MAN
05-15-2012, 01:51 PM
I have never had a single problem with the many DI guns that I have run, but knowing that I would now be running a sound
suppressor I switched over to a piston driven AR type rifle because it does run cooler and cleaner than a suppressed DI rifle.
I run the same sound suppressor on my M14s and AK47, all are piston driven.

OutdoorPursuitsCanada
05-15-2012, 02:34 PM
I don't fully understand how piston works or what its benefits are...so I don't have a dog in the fight.

I've only ever owner DI guns.

A DI system uses the gases from the spent cartridge to move the bolt carrier. A piston system uses just that, a piston in a cylinder to move the bolt (as used in an SKS)

mlehto
05-15-2012, 04:05 PM
I have been told that a piston driven AR cycles slightly faster as well. Something to do with gas compression being more of an issue with a longer gas system in a DI setup. Gases are still the main force behind the piston driven systen though just not as much I guess.

Onagoth
05-15-2012, 07:01 PM
A DI system uses the gases from the spent cartridge to move the bolt carrier. A piston system uses just that, a piston in a cylinder to move the bolt (as used in an SKS)

But that piston is still driven by gas is it not?

mlehto
05-15-2012, 07:59 PM
But that piston is still driven by gas is it not?

Yes but only between the barrel and gas block like an SKS, or CZ, so no long gas tube like a standard DI AR.

Onagoth
05-16-2012, 05:55 AM
This was my initial understanding, though I didn't fully understand the details.


http://www.youtube.com/watch?v=H3TVsekcFWo&NR=1&feature=endscreen

50calshooter
05-16-2012, 10:57 AM
That above video exaggerates the theory quite a bit.

The fact is all rifles need regular cleaning and proper maintenance. Sure if you never clean a gas gun there will be extensive carbon build up, but with regular maintenance it's IMO one of the most reliable systems out there. With piston, sure, it may run cleaner but will it be as reliable? More moving parts, more parts to wear out and replace and more wear and tear on the entire rifle itself....

Perhaps it's too close to give a definitive answer either way. So in that case, I'll stick with the original intended concept and design. Most of the best AR builders and manufacturers in the world still hold DI to the highest standard in their line-up, fact.

BuckingFastard
05-21-2012, 11:36 PM
Never owned I piston, probably never will. I'm with 50 on this one, I like the DI, all my ar's have been flawless in operation. Properly cleaned and maintained after every outing, riden hard but never put away dirty. I like the original design of the ar15, If its good enough for the sandbox it's good enough for me.

BigI
05-22-2012, 11:29 AM
Lets go a step further. My wife and daughter want me to buy AR15, don't want to brake the bank but nothing cheap either, preffer in .22lr. What to get?

OutdoorPursuitsCanada
05-22-2012, 11:42 AM
S&W MP22 is the way to go, sadly its still a restricted.

BigI
06-01-2012, 05:54 AM
What is this crap.Moderator get rid of this guy, doing it in other posts as well.

OutdoorPursuitsCanada
06-01-2012, 07:41 AM
Who and what are you talking about Bigl?

jwirecom109
06-01-2012, 07:48 AM
What is this crap.Moderator get rid of this guy, doing it in other posts as well.

You'll have to explain yourself on this one BigI

BuckingFastard
06-01-2012, 08:22 AM
I got your back bigI I seen it as well :)

OutdoorPursuitsCanada
06-01-2012, 08:35 AM
Somebody please enlighten me as to what you are talking about.

BuckingFastard
06-01-2012, 09:16 AM
Spammer early this morning

OutdoorPursuitsCanada
06-01-2012, 09:38 AM
Ah -that makes 100% more sense now lol - The post in question was already gone so Bigl's comment seemed strange. Good to know our mods are on top of the spam.

BuckingFastard
06-01-2012, 09:57 AM
Lol just read through the last page, ya it's pretty funny if you didn't see the spam post

Deniici
06-19-2012, 01:32 AM
Well I have to say at this point I think I prefer the piston over DI....but just barely. The piston does take less effort and time to clean. I did a comparison, between my POF piston, and Bushmaster DI. What I did was a mag dump. 10 mags, loaded with 30 rounds of 55grn PMC. Aimed fire on target, with no breaks in between mags. The POF ran flawlessly, stayed cool ie you could touch the bolt carrier. It was hot but not uncomfortably so. The bushmaster not so much, it started getting to hot after 8 mags, and finally puked on the 9th mag. I believe it to be heat related, as I finished off the last mag and a half in the POF. The bushmaster stopped feeding properly. After it cooled and a little oil added it was running fine.
I don't know how scientific this test was, but I was truly surprised at the difference. That all being said, if I had to hump a rifle all day, I'd take the bushy, it's much lighter.
Any thoughts?

BigI
06-19-2012, 08:14 AM
Was a Spammer allright, Polish one I think. On another note, wife is happy, got her a M&P15-22, will take it to the range on the weekend and see. I think she will have to fight our daughter over it.

50calshooter
06-19-2012, 08:40 AM
Well I have to say at this point I think I prefer the piston over DI....but just barely. The piston does take less effort and time to clean. I did a comparison, between my POF piston, and Bushmaster DI. What I did was a mag dump. 10 mags, loaded with 30 rounds of 55grn PMC. Aimed fire on target, with no breaks in between mags. The POF ran flawlessly, stayed cool ie you could touch the bolt carrier. It was hot but not uncomfortably so. The bushmaster not so much, it started getting to hot after 8 mags, and finally puked on the 9th mag. I believe it to be heat related, as I finished off the last mag and a half in the POF. The bushmaster stopped feeding properly. After it cooled and a little oil added it was running fine.
I don't know how scientific this test was, but I was truly surprised at the difference. That all being said, if I had to hump a rifle all day, I'd take the bushy, it's much lighter.
Any thoughts?

I guess it depends on what era your bushy is from (the older ones were pretty decent rifles), in theory the test you ran is of some value but comparing apples to oranges not so much. However, there is one thing that remains factual in your test. The heat factor, yes pistons run a little cooler but the heat shouldn't affect operation of the rifle (to a point and within reason) I wonder if there was something else to blame for the failure...

You also make a good point about weight savings with DI...

BigI
06-25-2012, 08:58 AM
Went through about 500 rounds of CCI with 0 issues with the M&P15-22. Sure could use that 50 round drum or Not. Wife loves it as do few friends. Now the mods start. Bipod on the way, red dot going on tonight.

Xeelee
01-22-2013, 02:23 AM
I was having this exact same dilemma a couple of months back. I was planning on building a SBR and couldn't decide between DI or piston. As has been stated already a properly maintained DI will run just fine. It's a given for the factory piston systems but I decided on DI. Why? Simply put DI has been around for a long time and well established. Parts are almost universally interchangeable and easily sourced (Well maybe up until a month or so ago). Piston systems are a bit newer and not really standardized yet with some parts being proprietary and not interchangeable between different manufacturers. This was enough to deter me from piston...for the moment anyways ;)

Neil Burke
01-22-2013, 02:11 PM
Keeping in mind that I don't have either at this point in time, given the choice, I'd go with a quality factory piston ar over a quality DI. For me the benefits are that it's keeps the thing cooler and the gases from getting everywhere. It just seems more efficient/better designed in that respect. As for the weight *shrugs* ARs are for the range atm anyways, a little more weight isn't going to kill me.

Chalk
01-22-2013, 09:45 PM
You means keeps the gas block hot and the chamber and bolt group slightly cooler. I love reading stuff on the piston ar's people make it sounds like all of the sudden their gun doesn't get warmer then room temperature because of this wizard crafted piston.

Satain
01-22-2013, 11:18 PM
You means keeps the gas block hot and the chamber and bolt group slightly cooler. I love reading stuff on the piston ar's people make it sounds like all of the sudden their gun doesn't get warmer then room temperature because of this wizard crafted piston.

http://www.youtube.com/watch?v=j7nEnF469FY
Plus I love the fact I am not hughing carbon when shooting. Never mind the part that cleaning is big time differance.
But to each there own...
And I own an ADCOR :p

Chalk
01-22-2013, 11:28 PM
Still not seeing a heat reading off where the gas block/piston is, just saying. As for the carrier group being 26' vs 58' honestly in my books, doesn't particularly matter. It is cooler but then again your AR wasn't built to melt so 20' ish of difference for a bunch more money for no real reason just doesn't make sense for what I look for. Others maybe it is, which is fine everyone is looking for what they fancy.

Epoxy7
01-23-2013, 02:23 AM
I like DI for handling, accuracy and cost. Less harmonic issues and they turn into tack drivers with a match SS barrel and match trigger. Many of the piston system AR rifles have chunky hand guards for the piston which makes for a less agile handling carbine.

I would consider piston for short SBR carbines and supressor use. In order to get comparable accuracy to a DI rifle heavier and higher quality barrels tend to be used. Core uses a SS barrel only on their piston setup.

Hybrid: ADCOR. DI style off the barrel to a piston held in the free float handguard. Long rod style connected to the BCG so no slapping the bolt. DI accuracy, piston reliability.

Cleaning: soak everything in G96. Most parts just wipe clean unless excessive round count. The piston takes scrubbing at the point where it's actuated. Plus the carbon is spewed all along the hand guards. Ultimately cleaning is a minimum advantage to the piston system.

50calshooter
01-23-2013, 08:05 PM
I said it before and Im guna say it again... Piston AR's are a solution to a problem that never existed. Pistons are just gucci for an already polished platform.

The argument for excessive gases and blowback is moot. Run a DI Mid-Length gas gun and there's absolutely zero reason to run Piston. Mid-Length DI guns run smoother, there is less wear and tear and the gas pressures are lower. Not only is there a reliability argument in favour of Mid-Length vs Piston, but Mid-Length gas is arguably more reliable then Carbine gas as well...

Knights Armament, Noveske, Daniel Defense and Bravo Company all use Mid-Length gas, over Piston.... You think there may be a reason the top AR manufacturers in North America use Mid-Length DI over Piston? I'd say so...

blaxsun
01-23-2013, 09:10 PM
I can think of a few applications where pistons will excel: suppression, select fire and SBR.

Satain
01-24-2013, 10:24 PM
Still not seeing a heat reading off where the gas block/piston is, just saying. As for the carrier group being 26' vs 58' honestly in my books, doesn't particularly matter. It is cooler but then again your AR wasn't built to melt so 20' ish of difference for a bunch more money for no real reason just doesn't make sense for what I look for. Others maybe it is, which is fine everyone is looking for what they fancy.
Correct but that also means that when dumpping large amount of rounds it won't burn off the lube as quick hence lowering you cycling/feed or extracting issue.
Accuracy like is higher for high end DI sure but in the case of ADCOR and my personal real world testing it has been muted.
As for cleaning if the rig was built with a hard chromed entire BCG then lube/cleaning is not really required as much.
As for 50cal's statement's it has become aware to me that you have never fired suppresed or have deep sixed your rigged then had to fire it asap.
As for you stating those company's then I can easly rebute you by saying that if it was top tier that you were talking about well then lets talk about the top of the food chain.
HK, LMT and SIG (Germany) all make AR version in piston configurations. Also all the high end security company's and also major army's in the world all have or in the process in changing there many service rifle into a piston system.
Also any DMR Marine will tell you that they would take there M14 over a AR15 any day and even more so in the sand box. Further more to that point the rumor mill is a buzz as it sounds like they might be switching back to the 1911's cause they would rather have the 45 ACP round and even though the M9 is fine they would rather have the 45 ACP round. Even though I wish that they would switch to the Glock 21 Gen 3 but that's just me.
Check and mate :p

Chalk
01-25-2013, 09:06 AM
I'm going to back off on the main debate here since my lack of actually owning a piston gun makes my argument points limited. But for a DMR saying a M14( or what ever configuration they got it in) over an AR-15... gee I wonder could it be the 7.62x51 being better suited for a DMR role then a 5.56x45? Unless you meant to put AR-10 (what ever variants of it) Then I want some sources specifically stating it.

50calshooter
01-25-2013, 11:25 AM
Correct but that also means that when dumpping large amount of rounds it won't burn off the lube as quick hence lowering you cycling/feed or extracting issue.
Accuracy like is higher for high end DI sure but in the case of ADCOR and my personal real world testing it has been muted.
As for cleaning if the rig was built with a hard chromed entire BCG then lube/cleaning is not really required as much.
As for 50cal's statement's it has become aware to me that you have never fired suppresed or have deep sixed your rigged then had to fire it asap.
As for you stating those company's then I can easly rebute you by saying that if it was top tier that you were talking about well then lets talk about the top of the food chain.
HK, LMT and SIG (Germany) all make AR version in piston configurations. Also all the high end security company's and also major army's in the world all have or in the process in changing there many service rifle into a piston system.
Also any DMR Marine will tell you that they would take there M14 over a AR15 any day and even more so in the sand box. Further more to that point the rumor mill is a buzz as it sounds like they might be switching back to the 1911's cause they would rather have the 45 ACP round and even though the M9 is fine they would rather have the 45 ACP round. Even though I wish that they would switch to the Glock 21 Gen 3 but that's just me.
Check and mate :p

I don't see it, but good talk, lol

Satain
01-26-2013, 06:10 AM
I'm going to back off on the main debate here since my lack of actually owning a piston gun makes my argument points limited. But for a DMR saying a M14( or what ever configuration they got it in) over an AR-15... gee I wonder could it be the 7.62x51 being better suited for a DMR role then a 5.56x45? Unless you meant to put AR-10 (what ever variants of it) Then I want some sources specifically stating it.
The problem is that they can spend a couple of K @ SEI to tune up an M14 that they have stock piled or by a Knights SR-25(or another high end ar10) but those rigs cost way more and also the supply chain has yet been swaped over. In light of how well the old war horse has still been preforming even though some that work for a certain company might leed you to blieve other wise the Marines have yet to be convinced to completely switch over. Hell even the big green machine even has some in reserve. It's like the energizer bunny. Hopefully soon it will be put to rest but only time will tell.

Epoxy7
01-26-2013, 03:05 PM
I'm kind of partial to the AR10 and other AR308 rifles. The M14 is a money pit to keep accurate. Even then the AR10 has it beat for accuracy.

I should add that AR308 rifles such as the POF one are piston. Personally I'd stick with DI. Also in a DM rifle you're less likely to be shooting as many rounds. ADCOR is supposed to be working on a 308 as well.

Cost and availability are the most likely factors for the M14 being used still. Plus the option is probably that or your regular AR rather than a DM 308 AR. So this or nothing. I'd like the M14 then too!

Ben
01-26-2013, 03:13 PM
I'm kind of partial to the AR10 and other AR308 rifles. The M14 is a money pit to keep accurate. Even then the AR10 has it beat for accuracy.

I should add that AR308 rifles such as the POF one are piston. Personally I'd stick with DI. Also in a DM rifle you're less likely to be shooting as many rounds. ADCOR is supposed to be working on a 308 as well.

Cost and availability are the most likely factors for the M14 being used still. Plus the option is probably that or your regular AR rather than a DM 308 AR. So this or nothing. I'd like the M14 then too!

I didn't know that - will surely be keeping my eyes open for it.

blaxsun
01-26-2013, 04:56 PM
Things I like about pistons: the upper receiver stays cleaner.
Things I don't like about pistons: all that crap has to go somewhere...

Satain
01-27-2013, 02:20 AM
I'm kind of partial to the AR10 and other AR308 rifles. The M14 is a money pit to keep accurate. Even then the AR10 has it beat for accuracy.

I should add that AR308 rifles such as the POF one are piston. Personally I'd stick with DI. Also in a DM rifle you're less likely to be shooting as many rounds. ADCOR is supposed to be working on a 308 as well.

Cost and availability are the most likely factors for the M14 being used still. Plus the option is probably that or your regular AR rather than a DM 308 AR. So this or nothing. I'd like the M14 then too!
Want to put your theroy to a real world test????
I am up for it. But don't complain if my computer comando skillz come up a little short ;)

Epoxy7
01-27-2013, 01:59 PM
Yup Id be willing to this spring. Meh forget computer skills. If you have a M14 let's go shoot this spring/summer. Fireball has an AR10 as well so he can join in. I'll put together some 175 SMK 43.4 varget loads for it and have some fun. I also have a DPMS LR308 scoped that would be fun with some 167 Lapua.

Satain
01-27-2013, 11:58 PM
Whoo!
GOC shoot out. Lets do this. 308 semi only and we will have to find a range long enough. You bring fireball and I will try to drag Oldsmobiler out.
We should turn this in to a GOC event. I will try to see if I can get a range set up. PM in bound.

Popurhedoff
01-28-2013, 01:08 AM
While there is nothing wrong with either system, but I do prefer the piston. Most of us here use our AR's at a range so a well maintained AR in either configuration is good to go. Where the difference will start to show is in places and useage like over here in the sandbox. Some tic's last a long time and you go through a lot of ammuniton, less dirt, gunk, carbon buildup is a good thing which equates to shooting more before the dredded 'Stoppage". After the Poop happens and its back to the site, clean your gear before you put it away.

I have enjoyed the merits of the pistion since the FNC1 A1. The Stoner DI design is good, but there is no reason to think that an upgraded design does not benifit and improve apon the orginal Stoner design. The Stoner DI system has been around for 50+ years... even old gun designs can get improved apon. Over here in Afghanistan, if I can get a hold of a Piston AR/M4, then I use my trusty 60 year old Type 2 AK-47.

Think of it like the Carb vs EFI argument, carbs were the apitomy or regulating fuel/air for the longest time... then some young upstart developed the EFI, for years afterwards there were untold comments about each... an us vs them mentality... now how many vehicles come normally aspirated? The design was improved apon, but some muscle heads still love their Carbs. I know I dont miss always tweaking that Elderbrock 750cfm double pumper double feed carb.


To summize, if its a range gun, you may not end up seeing the merits of the Piston vs DI, keep them both clean and have fun with them... BTW, I do have 2 DI AR's and they work great.

Cheers
Pop

Epoxy7
01-28-2013, 01:35 AM
Whoo!
GOC shoot out. Lets do this. 308 semi only and we will have to find a range long enough. You bring fireball and I will try to drag Oldsmobiler out.
We should turn this in to a GOC event. I will try to see if I can get a range set up. PM in bound.

Mission is 300 meters. Fireball and I are both members so we can have 1 guest each. Thinking Spring though. Have to get the LMT setup with my scope and find out which ammo it likes. Or get a match trigger for the AR10. The current one is iffy for a precision rifle.

Keep in mind if doing a service rifle match idea. I've never shot service rifle. So an intro to course of fire etc would be good. I've shoot RCMP course of fire for the Win M70 100 meters from 4 unsuported positions but that's it. Other than bench and screwing around off hand of course. Looking forward to learning and shooting.

I'll get the LMT setup.

Epoxy7
01-28-2013, 02:18 AM
While there is nothing wrong with either system, but I do prefer the piston. Most of us here use our AR's at a range so a well maintained AR in either configuration is good to go. Where the difference will start to show is in places and useage like over here in the sandbox. Some tic's last a long time and you go through a lot of ammuniton, less dirt, gunk, carbon buildup is a good thing which equates to shooting more before the dredded 'Stoppage". After the Poop happens and its back to the site, clean your gear before you put it away.

I have enjoyed the merits of the pistion since the FNC1 A1. The Stoner DI design is good, but there is no reason to think that an upgraded design does not benifit and improve apon the orginal Stoner design. The Stoner DI system has been around for 50+ years... even old gun designs can get improved apon. Over here in Afghanistan, if I can get a hold of a Piston AR/M4, then I use my trusty 60 year old Type 2 AK-47.

Think of it like the Carb vs EFI argument, carbs were the apitomy or regulating fuel/air for the longest time... then some young upstart developed the EFI, for years afterwards there were untold comments about each... an us vs them mentality... now how many vehicles come normally aspirated? The design was improved apon, but some muscle heads still love their Carbs. I know I dont miss always tweaking that Elderbrock 750cfm double pumper double feed carb.


To summize, if its a range gun, you may not end up seeing the merits of the Piston vs DI, keep them both clean and have fun with them... BTW, I do have 2 DI AR's and they work great.

Cheers
Pop

Keep in mind we have better metal conditioners and lubricants these days. Give G96 a try instead of CLP. This stuff helps for reliability and makes cleaning much faster. Also works in sub -50. Ask me how I know.

Precision DM rifles also benefit from DI in terms of greater accuracy potential.

blaxsun
01-28-2013, 06:39 AM
x2. G96 and Frog Lube.

Satain
01-28-2013, 04:24 PM
Keep in mind we have better metal conditioners and lubricants these days. Give G96 a try instead of CLP. This stuff helps for reliability and makes cleaning much faster. Also works in sub -50. Ask me how I know.

Precision DM rifles also benefit from DI in terms of greater accuracy potential.
I agree...
No doubt about it.

loki
01-30-2013, 04:02 AM
http://youtu.be/HhGih7eWI3E

Watch the whole vid if you have time but 3:35 to 4:19 wins the internet.... uhhhh I mean this argument :p. Winner = piston :la:.

PS NSFW.

Epoxy7
01-30-2013, 04:36 PM
An "unbiased" comparison of the AR Vs. AK.


http://www.youtube.com/watch?v=3VRrc2n0NXg&feature=player_detailpage

Suputin
02-15-2013, 11:27 AM
I have never had a single problem with the many DI guns that I have run, but knowing that I would now be running a sound
suppressor I switched over to a piston driven AR type rifle because it does run cooler and cleaner than a suppressed DI rifle.
I run the same sound suppressor on my M14s and AK47, all are piston driven.

That is amusing. I run DI on all my guns because I also run them suppressed. When suppressed, DI guns are considerably quieter (8-10 dB) than piston guns because all the piston systems vent excess high pressure gas to the atmosphere making them nearly impossible to get below the hearing safe threshold.

I have one gun that gets run suppressed most of the time and is used for endurance testing amongst other things. It hardly ever gets cleaned because it is my workhorse and I don't really care about it. Yet it rarely ever hiccups and runs like a champ. A suppressed DI gun may be a bit dirtier but that doesn't affect functioning in any normal conditions.

Suputin
02-15-2013, 11:43 AM
http://youtu.be/HhGih7eWI3E

Watch the whole vid if you have time but 3:35 to 4:19 wins the internet.... uhhhh I mean this argument :p. Winner = piston :la:.

PS NSFW.

THAT is GENIUS. :D

H2O MAN
03-25-2013, 07:34 AM
That is amusing. I run DI on all my guns because I also run them suppressed. When suppressed, DI guns are considerably quieter (8-10 dB) than piston guns because all the piston systems vent excess high pressure gas to the atmosphere making them nearly impossible to get below the hearing safe threshold.

I have one gun that gets run suppressed most of the time and is used for endurance testing amongst other things. It hardly ever gets cleaned because it is my workhorse and I don't really care about it. Yet it rarely ever hiccups and runs like a champ. A suppressed DI gun may be a bit dirtier but that doesn't affect functioning in any normal conditions.

My suppressed piston rifles run cool and clean with no hiccups and you find this amusing. That is strange.

http://i895.photobucket.com/albums/ac160/The_H2O_MAN/AR-100%20DAEWOO/IMG_4489.jpg

http://i895.photobucket.com/albums/ac160/The_H2O_MAN/X-15M4SVortexAR-100_zpsce0bb60b.jpg

Maple Leaf Pilgrim
04-02-2013, 11:42 AM
I own one example of each.

The Piston:
I have a PWS Mk112 (12.5"bbl) in FDE kitted out with an Aimpoint T1 and Troy VFG. Total weight is less than 7 pounds. During the trials phase I ran it about 1500 rounds between cleaning with no supplemental lubrication. There were no stoppages. The rifle runs on a long stroke piston system quite akin to the one found in the AKM, in fact, when I field stripped it, I recognized it right away. A mate of mine who is using one along the Af-Pak border has confirmed for me that it is a better choice for the desert over the M4s the men of 10 mountain are using and another bloke I know doing CPD work in Sierra Leone has said it works pretty much flawlessly in the jungle too. Now both are issued and both are fully auto with suppressors when required. I give the platform as designed by the guys in Boise an A+.

It has all the ergo of an AR and a very good chunk of the reliability accredited to the AKM. It is also only $2000.00-$2300.00 at most places that sell it in Canada.

The DI:
DD Mk18 Mod1 that I own is still in T&E with me as I get it set up and all my ducks in a row. I am no stranger to the DI system as I have used the L119/C8 and C7 quite successfully in various climates and have only ever had minors issues while deployed. The DI is a viable operating system and it requires only a little bit more attention while deployed (I also don't believe in safe queens and run my firearms hard civvy side).

In short if you gave me a HK416 (tried it and preferred the Mk112) or a Mk18 Mod1 or Mod0 I would not sweat it either way. It's the operator, not the tools that really count.

Mikthaniel
04-02-2013, 11:55 AM
Less parts, less weight in the DI...

Extra heat on the trigger assembly under sustained fire can cause issues...

Philosophy of Use is the biggest determining factor...

If I was going for some relaxed range time, either/or... If I was on the run in a survival situation DI... If I was pinned down laying steady suppressive fire I would go piston driven...

NorCalDustin
04-02-2013, 03:28 PM
Less parts, less weight in the DI...

Extra heat on the trigger assembly under sustained fire can cause issues...

Philosophy of Use is the biggest determining factor...

If I was going for some relaxed range time, either/or... If I was on the run in a survival situation DI... If I was pinned down laying steady suppressive fire I would go piston driven...
Very true... And we may even see this change in the future with coatings like Nickel Boron (no lubrication is used giving piston reliability)... Or Duracoat SL (I'm doing T&E on it professionally applied on two rifles right now)... etc..

Really though.. DI, Piston, Other... For most users it doesn't matter other than how available parts will be.

Grain
04-02-2013, 04:34 PM
...we may even see this change in the future with coatings like Nickel Boron

I really like what I've read and watched about nickel boron. IF I can find parts, I want to give them a whirl when I get back to finished my current AR build. Need to quit buying other things first...

NorCalDustin
04-02-2013, 06:21 PM
I've been fortunate enough to have ended up with a complete nickel boron setup.. Bolt, BCG, Gas Key, Upper, Charging Handle, and complete FCG...

I tell you what... It really makes the trigger feel nice and everything wipes clean... I've been testing the setup in a 7" barrel for almost a year... The first 1000 rounds of random steel and a little brass cased ammo just wiped right off the gun. I never lubed it.. I did find though with the really dirty ammo you end up with a lot of stuff in the lower (more than usual) which the first time i blew out with an air compressor. I think because nothing sticks to the upper that it falls into the lower.

Anyway, I dont feel I "clean" the gun anymore.. I just take a paper napkin and wipe it down with 1-2 passes and put it away... It's become my Go-to gun for days I dont have time to do a 10 minute cleaning.

Greenman
05-14-2013, 08:12 AM
As soon as I got me Adcor defence upper for my build , I cant say that I will ever go back to the old system . In fact I think that I will be dropping all my non piston rifles that I have left . Just as a question should this not change the classification to a Non restricted status due to the changed operation of the firearm .

50calshooter
05-14-2013, 01:00 PM
As soon as I got me Adcor defence upper for my build , I cant say that I will ever go back to the old system . In fact I think that I will be dropping all my non piston rifles that I have left . Just as a question should this not change the classification to a Non restricted status due to the changed operation of the firearm .

LOL, Good one

Satain
05-14-2013, 01:26 PM
LOL, Good one
Hey thatz not nice...
Some of us live in Hope you know :p
http://2.bp.blogspot.com/_19hkKJG0tKo/TD3yRqsD7-I/AAAAAAAABS8/-VUMEgOUf_M/s400/DaveNash_hope_bc.jpg

leibermuster
09-13-2014, 06:03 PM
PISTON = Heckler & Koch - HK416/417

DI= SR16 SR25 knights Armament Company KAC

Start there and work down from there.

superbad
10-05-2014, 12:02 PM
I guess it depends on what era your bushy is from (the older ones were pretty decent rifles), in theory the test you ran is of some value but comparing apples to oranges not so much. However, there is one thing that remains factual in your test. The heat factor, yes pistons run a little cooler but the heat shouldn't affect operation of the rifle (to a point and within reason) I wonder if there was something else to blame for the failure...

You also make a good point about weight savings with DI...
i think the new bushys are great, i got one 5 months ago and it has 3400 rounds without a single failure. i just replaced the rings on the bcg cause they looked a little beat up. Here is where i stand on piston vs di. More moving parts equals more failures, the di system has been improved over 40 years, piston ars barely have 5 years and alot of them have issues, they can be worked out but nevertheless issues. If canada allowed cans then id put one on a piston driven ar but they dont so di it is.

Suputin
10-06-2014, 08:12 AM
Piston is significantly worse for suppressed use. The piston systems all vent high pressure gas to the atmosphere which makes them essentially impossible to bring below the hearing safe 140 dB level.

awndray
10-06-2014, 08:45 AM
Here's what Armalite has to say.


TECHNICAL NOTE 54: DIRECT IMPINGEMENT VERSUS PISTON DRIVE

PURPOSE: To compare the merits of internal and external piston drive systems.

FACTS: The AR-15/M16 and the AR-10 family of rifles employ a unique gas powered operating system patented by Eugene Stoner in the 1950s. This gas operating system works by passing high pressure propellant gasses tapped from the barrel down a tube and into the carrier group within the upper receiver, and is commonly but incorrectly referred to as a “direct impingement” system.

The gas expands within a donut shaped gas cylinder within the carrier. Because the bolt is prevented from moving forward by the barrel, the carrier is driven to the rear by the expanding gasses and thus converts the energy of the gas to movement of the rifle’s parts.

The bolt bears a piston head and the cavity in the bolt carrier is the piston sleeve. It is more correct to call it an “internal piston” system.

Most previous semiautomatic rifles use an “external piston” system operating in a gas cylinder mounted outside the receiver, but instead attached to the barrel. Propellant gasses expand within the cylinder and force the piston to the rear. The piston either contacts a rod that and drives a carrier to the rear (FAL), or are part of, connected to, or strike a rod segment that passed around the action to cam and move the bolt (M1, M14, AK- 47, SCAR). In some cases the piston is fixed and the movable cylinder drives the rod (AR-180).

ADVANTAGES AND DISADVANTAGES: The Stoner system provides a very symmetric design that allows straight line movement of the operating components. This allows recoil forces to drive straight to the rear. Instead of connecting or other mechanical parts driving the system, high pressure gas performs this function, reducing the weight of moving parts and the rifle as a whole.

In external piston systems, the path of the operating force is mechanically shifted around the action, resulting in a considerable mass of moving parts moving outside the centerline of the firearm and producing various torques within the system.

There is a common belief that the external piston operated systems are less accurate than the Stoner internal piston system because the operating parts start moving while the bullet is still in the bore. This is not true: Army Ordnance tests conducted in the 1960s revealed that the bullet is 25 feet out of the bore of the M1 and 15 feet out of the bore of the M14 before any operating part begins to move. It is more likely that the imbalances of the external piston, operating rod, cylinder, and other parts hanging on the barrel produce disruptive vibrations as the bullet exits the bore.

Although movement of the operating parts while the bullet is in the bore isn’t apparently a culprit in reducing the accuracy of external piston systems, the inherent accuracy of the Stoner internal piston system has been consistently confirmed in competitive shooting. In all events that allow use of any mechanism the shooter wishes, the Stoner internal piston system is prevailing. Few competitive shooters use the Garand or Kalashnikov systems, and none observed now use the FAL system. In American Service Rifle and NRA competition, the external-piston operated rifles are considered a significant disadvantage.

There is a debate about which system remains cleanest. The internal piston system tends to leave propellant residue in the receivers, while the external piston systems keep the residue outside the action in the cylinder. External piston driven systems, however, tend to allow more external dirt into the action because of the openings required for various connecting members (operating rod, bolt lugs, etc). Comparison tests of the M16 and the M-14 before Desert Storm confirmed the superiority of the Stoner system in sand and dust tests, and recent testing has proven that proper cleaning of either system provides excellent reliability.

ArmaLite concludes that there is no technical advantage to an external piston system employing current ammunition. It will likely, however, provide external-piston systems to the market as customers demand.

As a last note, misuse of the term “direct impingement” to describe the Stoner system is so common that it has confused the issue. A direct impingement system like that of the AG-42 Ljungman or the French MAS-49 rifle taps gas at the barrel and passes it into the receiver in a way similar to the M16, (the source of the confusion) but deposits it into a small, shallow cup or pocket in the carrier. The gas expands there and drives the carrier to the rear with relatively little pneumatic advantage. The addition of the Stoner internal piston system provides significantly more pneumatic advantage to the rifle and little of the blast of escaping gas at the breech end of the gas tube of the earlier rifles.
http://www.armalite.com/images/Tech%20Notes%5CTech%20Note%2054,%20Gas%20vs%20Op%2 0Rod%20Drive,%20020815.pdf

Booletsnotreactwell
12-06-2014, 12:11 PM
tl;dr version

Piston guns can be as accurate as DI if done properly/high quality, in the real world that means expensive, like H&K 416 expensive...

Differences between AR15 DI and elitist as per definition DI system is the addition/elimination of the gas key

With today's advances in lubricant and knowledge regarding how and when to employ it, you can run a rack grade DI AR into the thousands of rounds on full auto without any issues.

Piston AR will show it's strengths in very short barreled variants. DI system will purr in perfection at rifle configuration.

superbad
12-08-2014, 11:13 PM
from my experience i find piston ars to be front heavy, they get hot up front, they also get pretty dirty just in a different place. However, they do work very well with silencers. I like di because its been around for a very long time thus its as good as it gets, where piston ars are fairly new in comparison in the ar 15 platform. i really dont like the extra weight up front, specially when having to run thru a course and your last shots are long shots standing, even a few extra ounces can affect accuracy. piston ars are a little bit more money, however its still an ar 15 and ill take either over any other platform.

Mark-II
12-09-2014, 06:55 AM
I'm tempted by a piston gun, if only because I'm a gadget guy and like different stuff. Otherwise the gas guns do it for me. I probably clean mine more often than I need to, because after a few hundred rounds the grease looks pretty filthy, but even if I don't bother it still does what I need it to.

A quick cleaning involves wiping out the upper and BCG, painting on new grease, and putting it back together. Not really a big deal.

superbad
12-09-2014, 12:50 PM
i was taught to clean every firearm as soon as i get home, i do complete take downs. My ar takes me about 35 minutes, i take the entire bolt carrier group apart, extractor, i clean everything. the trigger assembly gets taken out as well and cleaned. the chamber,m4 ramps, bore,and buffer spring gets cleaned and lubricated as well as the buffer gets inspected for cracks. i use a knife to scrape any caked on stuff on the bolt and inside the bcg i use steel wool where the bolt faces. i take down all my handguns, shotguns and rifles. I will say that the shotgun probably doesnt need it, but once i get in the habit of not cleaning them after i fire them, then its a slippery slope downhill.i also alternate between 2 bcgs, and replace rings every 2500 rounds, gas tube at 5000 and barrel at 25000 because i only run premium american ammo, if i was using norinco or steel cased id probably need a new barrel at 10,000.

Fredo
12-10-2014, 06:43 PM
i was taught to clean every firearm as soon as i get home, i do complete take downs. My ar takes me about 35 minutes, i take the entire bolt carrier group apart, extractor, i clean everything. the trigger assembly gets taken out as well and cleaned. the chamber,m4 ramps, bore,and buffer spring gets cleaned and lubricated as well as the buffer gets inspected for cracks. i use a knife to scrape any caked on stuff on the bolt and inside the bcg i use steel wool where the bolt faces. i take down all my handguns, shotguns and rifles. I will say that the shotgun probably doesnt need it, but once i get in the habit of not cleaning them after i fire them, then its a slippery slope downhill.i also alternate between 2 bcgs, and replace rings every 2500 rounds, gas tube at 5000 and barrel at 25000 because i only run premium american ammo, if i was using norinco or steel cased id probably need a new barrel at 10,000.

And I thought I had OCD!

Booletsnotreactwell
12-11-2014, 08:51 AM
I think it's a myth that the AR15 series needs to be cleaned a lot. Most of it originating from the early failures in the military from being marketed as a self cleaning firearm and the bad ammo that was issued.


I've done tactical scenario shoots where me and a bunch of guys set up the range like those tactical carbine classes and ran similar drills. Took a 20" DI AR that had roughly 1200 rounds through it and burned through an additional 1150rds (or whatever the Norinco crate holds) of well yes Norinco ammo.


Stopped a few times, cracked the bolt back and sprayed G96 into everything and then kept gunning. Not a single FTF.

Mark-II
12-11-2014, 11:27 PM
CLP is like the modern equivalent of using a blow tube between shots in a BPCR, I suppose ;)

Keeps the gunk soft

superbad
12-20-2014, 05:28 PM
i also put new sheets and duvet covers on every night before i take a shower, maybe i should talk to someone about it lol.

incorrigible
02-20-2015, 07:54 PM
not sure if this has been touched on as I haven't read the whole thread. However being a Piston guy I found it a bit frustrating that there were no options out there that I have found so far for a 300 blk build I'm working on. On my 5.56 if it breaks, which it shouldn't, a piston setup would be harder to fix to due lack of available parts which would be an issue for a SHTF type of rifle.

Non-phixion
07-26-2016, 06:04 PM
DI was the way god intended it to be. DI for life.

Grizz Axxemann
07-27-2016, 10:20 AM
I like the KISS principle. DI is actually pretty simple. I'm pretty glad I bought an AR when I did. I had no idea what I was missing out on before. I just wish the LOP was about 2 or 3 inches longer.

protozen
08-18-2016, 10:51 PM
I like piston guns, but comparing DI and Piston AR's I've had, I'm inclined to vote DI.

B..
07-28-2017, 09:28 PM
DI......... Just a little extra cleaning sometimes. Just remember to keep it lubed and it'll run.

H2O MAN
07-29-2017, 06:05 AM
3063

The DI AR10 / M110 is being replaced by a piston HK

Doug_M
07-29-2017, 06:50 AM
As long as the rifle has a track record for reliability I'd say it doesn't matter. Both are gas operated magazine fed semiautomatic rifles in the end.