What's your choice, and comments??

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

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...

No,no, no offense I'm picking people's brains here.

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.

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.

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.

Quote from: DonRow on January 06, 2012, 03:54:47 PM

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.

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.

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/

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.

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.

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.

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.

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.

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.

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.

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!)

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...

 Depends on what piston system, as some are inferior then the others. I am big fan of the LWRC rifles..  Lifetime warranty as well.