DI vs Piston for .308 AR?

DocGlenn

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Jan 12, 2006
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North Georgia
I'm looking for a .308 AR (accurate, 16" barreled that I can run suppressed) and in doing my research, it seems that most of the highly reguarded 308's seem to be DI. GAP, KAC, Les Baer, JP, LaRue are all DI (I think). POF seems to be one of the few piston rifles in 308 caliber that get a lot of good press (if I'm missing someone let me know). So is the 308 AR better suited for a DI system? I really like how clean my LWRC piston gun runs, and was looking for a piston .308, but DI seems to be much more popular. Am I mising something here? Educate me please!
 
Re: DI vs Piston for .308 AR?

It's the same debate with the AR-15 platform. There is nothing wrong with the DI system. I have a POF piston AR-15 but I am having APA build me a custom 308 AR gun. For that I chose DI for a variety of reasons. Mainly, I will be shooting suppressed and I think the adjustable gas blocks offered can be fine tuned more easily than the current gas piston systems on the market.

Both systems are fine and I really dont think you can go wrong either way. POF and LWRC make excellent guns. GAP and APA built guns speak for themselves.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BCP</div><div class="ubbcode-body">POF 16" is really nice, LMT is really nice, or you could build your own.

From what I hear piston makes running suppressed much better, I don't know only really shot suppressed pistol. </div></div>

From my experience it makes little difference if it is piston or DI.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">.308 AR (accurate, 16" barreled that I can run suppressed)</div></div>
The advantage of a piston is running suppressors (and cleaner). That said, I went through the same thought process last year. I have the LWRC M6A3 and 6.8 PSD. However, given that round count is usually lower in a 308 (unless you're in a war); my priority for a 308 was different and I wasn't worried about cleaning it. I wanted accuracy in a semi-automatic and OBR users bragged about it. It didn't disappoint. Also, I was not planning to buy a suppressor. What added to my decision at the time was the REPR's teething problems with the mag catch and gas selector knob sticking. The mag problem was fixed. When I was researching accuracy reports from users, LWRC fans always brushed off its accuracy at that time and touted that "it's a battle rifle". Recent accuracy reports (see recent post here with REPR review) seems good; much better than previous reports of it being "MOA". After a year of production and development, and recent reports - I don't think you can go wrong. So if your priority is using a suppressor on a 308 semiauto, get a LWRC (or POF). I'm very pleased with my OBR. Good luck.
 
Re: DI vs Piston for .308 AR?

Keep an all LWRC stable with a REPR. They are tops, in fit and finish, and run like swiss watches. They take KAC paterned mags, (P-Mags), and work very well with a suppressor in mind. Clean and cool. The piston haters will tell you it is an unproven system, well I say how long has the FAL been around? That's what I thought! The LWRC REPR was designed as a piston. I have owned a DI 308, and a damn good one in the KAC SR-25. It was accurate, reliable, and alot of fun, until you have to clean it after 100+ rounds suppressed. My REPR has gone 400+ rounds in a weekend without a bobble suppressed. It cleaned up in a fraction of the time. I have never seen a 308 DI gun do it. I say keep yourself an all LWRC stable. JPG
 
Re: DI vs Piston for .308 AR?

I hear you brother. It did feel like bringing a red-headed stepchild home. Perhaps I have room for another 308 - REPR style; now that the bugs are worked out. I'm most impressed with how they keep innovating and bringing to market so quickly what the customers want. Your points are valid - my LWRC's are perfect.
 
Re: DI vs Piston for .308 AR?

I send a lot of rounds through a suppressed DI gun. My Noveske rifle has gone 350+ rounds suppressed without a field strip and without a problem. If the carrier ever starts to look dry I squirt "machine gunners lube"( which is probably synthetic motor oil) on the carrier and into those little holes on the carrier. I've never run it to failure but by keeping the bolt wet I'm pretty sure it would go over 1000. As far as cleaning goes, I usually spray the carbon off with brake cleaner or MPRO 7 (Which does the same thing). Then I re-apply oil. Done.
 
Re: DI vs Piston for .308 AR?

I would think a noveske barrel with a switch block would be best in you're situation. For what it's worth, I've always heard that di was better for accuracy because you're not sending the harmonics thru the barrel that you would with a piston gun. I heard that's why hk had to beef the barrel up on the production hk-416. I heard they were getting to much bullet stringing. I've also never seen precision match shooters going the piston route.

Hope that helps for what it's worth!!!
 
Re: DI vs Piston for .308 AR?

Thanks guys. I appreaciate your info and feedback. Will probably go talk to the guys at APA and see what they have to say about it also. Lots of different things to consider before taking the plunge.
 
Re: DI vs Piston for .308 AR?

I built a piston operated AR-15 and found it to be only cooler running. The chamber will still get dirty, there is no way around that, and piston systems themselves are extremely dirty and as easy to clean as one would think. DI isn't bad at all, if aint broke don't fix it.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RyanScott</div><div class="ubbcode-body">Piston .308s are unproven. Hell they are unproven in 5.56mm except the HK, and that just trades DI issues for piston issues. </div></div>
Most uneducated post I've read in weeks...
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RyanScott</div><div class="ubbcode-body">Piston .308s are unproven. Hell they are unproven in 5.56mm except the HK, and that just trades DI issues for piston issues. </div></div>
<span style="font-weight: bold">Most uneducated post I've read in weeks...</span> </div></div>

I agree with you on that!
 
Re: DI vs Piston for .308 AR?

I jumped on the "gotta have a piston operated" bandwagon (in 5.56), and I am now off that wagon. Yeah it's neat to dump a 30 round mag as fast as you can, and pull the bolt out to see how cool it is, but that's about it. Their really isn't an advantage to going piston. does the bolt stay cleaner sure; what's the trade off? You might end up with an unreliable system that has signs of carrier tilt and consistently malfunctions. The bolt carrier groups can get very dirty and still run flawlessly, just keep the parts well lubed. Stick with DI gas.
 
Re: DI vs Piston for .308 AR?

Theoretically, I believe the piston system should be more reliable in adverse conditions. The bolt and action run cooler and do not get gummed with carbon as quickly. The Piston areas get very dirty - which could cause malfunction, but the piston design can negate this to a great extent (LWRCI for example). Accuracy can also be excellent with a piston system.

Is it worth the extra $700 for a piston design? That’s an individual choice. There are plenty on this board that will spend an extra $1,000 on an optic for a marginal improvement that probably doesn’t make much of a difference in the long run. I suppose the same could be said for firearms too.

I have used LWRCI rifles and they are excellent in quality and function, but they are not “magical” in any way.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hopps</div><div class="ubbcode-body">Adverse conditions...like a firefight in a dust chamber?

</div></div>

Agreed, I can't think of any condition that would allow for a gas piston system to excel over a DI gas system. You still have to lube a bolt carrier group as you do a DI gas bolt carrier group. That lube attracts dust the same in either system.

By the way, I just got back from testing out my new 12.5 inch DI gas upper which is a replacement for my 12 inch piston upper that consistently malfunctioned do to carrier tilt. I put 410 rounds through it in about an hour and a half. The only two malfunctions were failure to lock back on an empty magazine (I believe the magazine to be the culprit because it was the same mag both times). Only had a light coat of lube on it from my last cleaning too. I would have shot more, but I ran out of ammo. I got the gun pretty hot; I have some discoloration around the front sight post base, and It ran just fine.

My old piston system on the other hand, didn't really stay that clean either, probably due to the metal shavings in my upper and lower receiver from the bolt carrier grinding away at my receiver extension and lower receiver. It also had a major problem cycling as you can imagine.

Nothing wrong with DI gas systems; if it isn't broke don't fix it. If you really want a piston operated 308, then buy a gun was designed to run a piston system like an AK Saiga or an FN.
 
Re: DI vs Piston for .308 AR?

Oh, and one more thing, a piston system doesn't keep the rifle any cleaner when running a suppressor; those gasses are still pushed back into the bore and chamber.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body">I jumped on the "gotta have a piston operated" bandwagon (in 5.56), and I am now off that wagon. Yeah it's neat to dump a 30 round mag as fast as you can, and pull the bolt out to see how cool it is, but that's about it. Their really isn't an advantage to going piston. does the bolt stay cleaner sure; what's the trade off? You might end up with an unreliable system that has signs of carrier tilt and consistently malfunctions. The bolt carrier groups can get very dirty and still run flawlessly, just keep the parts well lubed. Stick with DI gas. </div></div>
I'm curious... Have you ever seen a piston AR fail or become less reliable because of "carrier tilt"? Do you even know what it is? I've personally seen over 10,000 rounds run thru a piston AR. Yes, there were signs of "carrier tilt". Did the AR function any less reliably because of "carrier tilt"?... NO. Carrier-tilt, by virtue of physics, reaches a certain point with regard to wear and then ceases to wear the rifle any further... Long before any "real" damage is done.
It's been my experience, after having actually fired tens of thousands and maybe even hundreds of thousands of rounds thru both systems (mostly DI) that the DI system fails far more often... Because of the way it operates.
Oh, by the way, you're right about the inside of the "suppressed" piston gun. It does get just as filthy as a DI gun. Just does it less quickly.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body">Oh, and one more thing, a piston system doesn't keep the rifle any cleaner when running a suppressor; those gasses are still pushed back into the bore and chamber. </div></div>

On my 10.5 SBR 5.56 with suppressor and a Adam's Arms piston kit it runs a LITTLE cleaner than GI system but NOT much. I would imagine same for a 7.62 system. Good thing about the AA system it was a cheaper way to find out than a complete upper. Kit was $250 and runs 100%, but with the little it helped clean it up the $250 could have been better spent.
 
Re: DI vs Piston for .308 AR?

From the army tests involving the H&K piston-driven rifle in their 2007 weapons trials.

"Complicating the Army search for higher effectiveness in the M4 is a number of observations of M4 gas piston alternatives that suffer unintended design problems. The first is that many of the gas piston modifications for the M4 isolate the piston so that piston jams require the entire weapon be disassembled. The second is that gas piston alternatives use an off-axis operation of the piston that can introduce carrier tilt, whereby the bolt carrier fails to enter the buffer tube at a straight angle resulting in part wearing. The third is that the use of a sound suppressor results in hot gases entering the chamber, regardless of a direct-gas impingement or gas piston design choice."

I firmly believe that not only does DI have less moving parts and lower weight, but it can also be driven to greater measure of accuracy than any piston driven AR. Since this is Sniper's Hide and not "20-round mag dumps", I'm guessing accuracy is important, and "how cool is your bolt after a mag dump" isn't as big a deal. Properly lubed, DI systems run great.

There are a number of advantages to a DI system. IMO piston systems are a solution looking for a problem.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: djkest</div><div class="ubbcode-body">From the army tests involving the H&K piston-driven rifle in their 2007 weapons trials.

"Complicating the Army search for higher effectiveness in the M4 is a number of observations of M4 gas piston alternatives that suffer unintended design problems. The first is that many of the gas piston modifications for the M4 isolate the piston so that piston jams require the entire weapon be disassembled. The second is that gas piston alternatives use an off-axis operation of the piston that can introduce carrier tilt, whereby the bolt carrier fails to enter the buffer tube at a straight angle resulting in part wearing. The third is that the use of a sound suppressor results in hot gases entering the chamber, regardless of a direct-gas impingement or gas piston design choice."

I firmly believe that not only does DI have less moving parts and lower weight, but it can also be driven to greater measure of accuracy than any piston driven AR. Since this is Sniper's Hide and not "20-round mag dumps", I'm guessing accuracy is important, and "how cool is your bolt after a mag dump" isn't as big a deal. Properly lubed, DI systems run great.

There are a number of advantages to a DI system. IMO piston systems are a solution looking for a problem. </div></div>

How does all that unnecessary heat impact a precision AR? Especially on a .308 it seems like it could get excessive VERY quickly, and cause some metal to expand and contract over time. That's the main reason I personally have an interest in precision piston .308 AR's.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body">I jumped on the "gotta have a piston operated" bandwagon (in 5.56), and I am now off that wagon. Yeah it's neat to dump a 30 round mag as fast as you can, and pull the bolt out to see how cool it is, but that's about it. Their really isn't an advantage to going piston. does the bolt stay cleaner sure; what's the trade off? You might end up with an unreliable system that has signs of carrier tilt and consistently malfunctions. The bolt carrier groups can get very dirty and still run flawlessly, just keep the parts well lubed. Stick with DI gas. </div></div>
I'm curious... Have you ever seen a piston AR fail or become less reliable because of "carrier tilt"? Do you even know what it is? I've personally seen over 10,000 rounds run thru a piston AR. Yes, there were signs of "carrier tilt". Did the AR function any less reliably because of "carrier tilt"?... NO. Carrier-tilt, by virtue of physics, reaches a certain point with regard to wear and then ceases to wear the rifle any further... Long before any "real" damage is done.
It's been my experience, after having actually fired tens of thousands and maybe even hundreds of thousands of rounds thru both systems (mostly DI) that the DI system fails far more often... Because of the way it operates.
Oh, by the way, you're right about the inside of the "suppressed" piston gun. It does get just as filthy as a DI gun. Just does it less quickly. </div></div>

Here is what happened to my receiver extension from what I would call carrier tilt; and yes it did cause malfunctions. From what I could tell the bolt carrier group grinding into the the receiver extension slowed the BCG down enough that I could actually feel it cycling (very sluggish). The BCG had a tendency to get hung up on my magazine. Slapping the bottom of the magazine usually cleared this malfunctions.


P1020224.jpg


I don't doubt that you or anyone as fired thousands of rounds from different gas piston systems without major hick ups. For me on the other hand, am at a 100% failure rate for gas piston operated ARs (This was my first and last). Including all of my issued weapons, I have had well over 20 DI gas operated ARs, M16s, and M4s, and I cannot say I had any problems that were directly related to the gas impingement system or the BCG getting to hot or dirty. A little bit of maintenance has always kept them functioning properly. The DI system is a well proven design to me that I will be sticking with.
 
Re: DI vs Piston for .308 AR?

I have piston and DI, I like both. My 308 is DI, don't have a DI 308, just a few 5.556s.

My favorite rifle of them all, is well, all of them.

Just get the one you like, that works for the job you are aiming for.

Our 308 di gun is the R25, its accurate to me and I must say being a 308 it is a real joy to clean. Everything is bigger and easier to get a toothbrush into, so it being DI is not that big of a deal. The POF guns are really neat, don't get me wrong, if you an afford them, get a higher end, but if you lube correctly (which I was not at the start of my AR world) they run like Forest Gump with a truck chasing him.
 
Re: DI vs Piston for .308 AR?

Its only natural to defend ones purchase choices.we all do. the ar piston track record in the past is bad. I remember when they were pitching them 30 years ago, and they were junk.the ar's bolt design was just not designed for a piston rig,period .I guess in sbr's suppressed there are some that like them. the fact is, D I will serve you well and it has the longest track record by leaps and bounds over any ar style piston rig. plus keep in mind, certain companies are trying to make money, and in their videos the only way they can sell their product,is by besmerching D I,which is pathetic.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: command450</div><div class="ubbcode-body">Its only natural to defend ones purchase choices.we all do. the ar piston track record in the past is bad. I remember when they were pitching them 30 years ago, and they were junk.the ar's bolt design was just not designed for a piston rig,period .I guess in sbr's suppressed there are some that like them. the fact is, D I will serve you well and it has the longest track record by leaps and bounds over any ar style piston rig. plus keep in mind, certain companies are trying to make money, and in their videos the only way they can sell their product,is by besmerching D I,which is pathetic. </div></div>

Actually, .308 AR's have been very iffy until recently. There were several reported reliability issues. Currently, DI and Pistons are very reliable. Accuracy is very much the same if you use the same quality parts. The bullet is out of the barrel before the piston starts moving. It was proven a while ago.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body">I jumped on the "gotta have a piston operated" bandwagon (in 5.56), and I am now off that wagon. Yeah it's neat to dump a 30 round mag as fast as you can, and pull the bolt out to see how cool it is, but that's about it. Their really isn't an advantage to going piston. does the bolt stay cleaner sure; what's the trade off? You might end up with an unreliable system that has signs of carrier tilt and consistently malfunctions. The bolt carrier groups can get very dirty and still run flawlessly, just keep the parts well lubed. Stick with DI gas. </div></div>
I'm curious... Have you ever seen a piston AR fail or become less reliable because of "carrier tilt"? Do you even know what it is? I've personally seen over 10,000 rounds run thru a piston AR. Yes, there were signs of "carrier tilt". Did the AR function any less reliably because of "carrier tilt"?... NO. Carrier-tilt, by virtue of physics, reaches a certain point with regard to wear and then ceases to wear the rifle any further... Long before any "real" damage is done.
It's been my experience, after having actually fired tens of thousands and maybe even hundreds of thousands of rounds thru both systems (mostly DI) that the DI system fails far more often... Because of the way it operates.
Oh, by the way, you're right about the inside of the "suppressed" piston gun. It does get just as filthy as a DI gun. Just does it less quickly. </div></div>

Here is what happened to my receiver extension from what I would call carrier tilt; and yes it did cause malfunctions. From what I could tell the bolt carrier group grinding into the the receiver extension slowed the BCG down enough that I could actually feel it cycling (very sluggish). The BCG had a tendency to get hung up on my magazine. Slapping the bottom of the magazine usually cleared this malfunctions.


P1020224.jpg


I don't doubt that you or anyone as fired thousands of rounds from different gas piston systems without major hick ups. For me on the other hand, am at a 100% failure rate for gas piston operated ARs (This was my first and last). Including all of my issued weapons, I have had well over 20 DI gas operated ARs, M16s, and M4s, and I cannot say I had any problems that were directly related to the gas impingement system or the BCG getting to hot or dirty. A little bit of maintenance has always kept them functioning properly. The DI system is a well proven design to me that I will be sticking with. </div></div>

That carrier tilt is not normal. I have over 10k through my LMT and it had some carrier tilt, but nothing like that. I will never run a piston AR without a POF or PWS enhanced buffer tube, just like i will never run my DI ARs without a properly staked/installed carrier key. There is something wrong with yours and I honestly think you are being a little dramatic about it without even giving it another chance. I've had DI uppers that had problems that made them a single shot AR and while it was very frustrating, I didn't give up on them without giving the manufacturer a chance to make it right. What are you going to do if you get a DI upper that has issues? Are you going to give up on ARs altogether?
 
Re: DI vs Piston for .308 AR?

I have had very good luck with my REPR once I got through the growing pains.
All the ones they sell now are good to go.
I shoot suppressed a lot and it is very very clean.
The only issue I'm having is copper building up in the gas selector area. After about 200 rounds it gets really hard to turn and after 350 rounds I can't turn it at usually.
A quick clean and it's back to 100%. For more info on this call LWRC, they are happy to talk with you about it.
Accuracy was horrible until I found a load it liked. It's shoots sub MOA now with 175's 43.5grs of Varget loaded 2.81+ OAL. Groups really good with SW's Ammo as well. It's a hell of a gun.
 
Re: DI vs Piston for .308 AR?

Supressed=piston
Unsupressed=ford vs chevy


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KillShot</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: RyanScott</div><div class="ubbcode-body">Piston .308s are unproven. Hell they are unproven in 5.56mm except the HK, and that just trades DI issues for piston issues. </div></div>
<span style="font-weight: bold">Most uneducated post I've read in weeks...</span> </div></div>

I agree with you on that! </div></div>
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: paulosantos</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body">I jumped on the "gotta have a piston operated" bandwagon (in 5.56), and I am now off that wagon. Yeah it's neat to dump a 30 round mag as fast as you can, and pull the bolt out to see how cool it is, but that's about it. Their really isn't an advantage to going piston. does the bolt stay cleaner sure; what's the trade off? You might end up with an unreliable system that has signs of carrier tilt and consistently malfunctions. The bolt carrier groups can get very dirty and still run flawlessly, just keep the parts well lubed. Stick with DI gas. </div></div>
I'm curious... Have you ever seen a piston AR fail or become less reliable because of "carrier tilt"? Do you even know what it is? I've personally seen over 10,000 rounds run thru a piston AR. Yes, there were signs of "carrier tilt". Did the AR function any less reliably because of "carrier tilt"?... NO. Carrier-tilt, by virtue of physics, reaches a certain point with regard to wear and then ceases to wear the rifle any further... Long before any "real" damage is done.
It's been my experience, after having actually fired tens of thousands and maybe even hundreds of thousands of rounds thru both systems (mostly DI) that the DI system fails far more often... Because of the way it operates.
Oh, by the way, you're right about the inside of the "suppressed" piston gun. It does get just as filthy as a DI gun. Just does it less quickly. </div></div>

Here is what happened to my receiver extension from what I would call carrier tilt; and yes it did cause malfunctions. From what I could tell the bolt carrier group grinding into the the receiver extension slowed the BCG down enough that I could actually feel it cycling (very sluggish). The BCG had a tendency to get hung up on my magazine. Slapping the bottom of the magazine usually cleared this malfunctions.


P1020224.jpg


I don't doubt that you or anyone as fired thousands of rounds from different gas piston systems without major hick ups. For me on the other hand, am at a 100% failure rate for gas piston operated ARs (This was my first and last). Including all of my issued weapons, I have had well over 20 DI gas operated ARs, M16s, and M4s, and I cannot say I had any problems that were directly related to the gas impingement system or the BCG getting to hot or dirty. A little bit of maintenance has always kept them functioning properly. The DI system is a well proven design to me that I will be sticking with. </div></div>

That carrier tilt is not normal. I have over 10k through my LMT and it had some carrier tilt, but nothing like that. I will never run a piston AR without a POF or PWS enhanced buffer tube, just like i will never run my DI ARs without a properly staked/installed carrier key. There is something wrong with yours and I honestly think you are being a little dramatic about it without even giving it another chance. I've had DI uppers that had problems that made them a single shot AR and while it was very frustrating, I didn't give up on them without giving the manufacturer a chance to make it right. What are you going to do if you get a DI upper that has issues? Are you going to give up on ARs altogether?</div></div>

If I have any upper that is running a system that is a deviation from the original proven Stoner design; be it piston, mid length gas, carbine or pistol length gas, or any new operating system, that is continuously malfunction, you are damn right I am going to shit can it and go back to what I know to be a proven design.

As for the manufacturer, I tried that route. Sent them the same picture plus a few more. Their reply was "We believe the metal shavings are just the dry lube finish that we apply to the inside of all of our receiver extensions, clean it up and you'll be good to go." They then went on to comment about all the "work" I did to my gun (changed out the pistol grip, added a Magpul bad lever, and installed KNS anti walk pins)they implied that those modifications may have caused the carrier tilt. After a reply like that I felt that I would get nowhere with that kind of ignorance and I decided not to deal with them anymore; sell my upper, keep the lower as it is now a registered SBR, and put a DI system on it.

Even when it wasn't malfunctioning I saw no significant benefit over a DI gas system. Was the BCG cold to the touch after dumping a 30 round mag? Yeah. Is this a benefit I need? NO, I am not in the habit of dissembling my rifles and carbines immediately after rapid fire. Did the BCG stay a little cleaner? Yeah. Again is this something I need? No, I usually wait until the bore needs to be cleaned before I clean and I have never had a problem with the DI systems on that time line. If they do get too nasty, I quickly wipe the BCG down with a rag, lube it up, and I am back in action (a total of maybe two minutes of maintenance).

So I feel that for me to dump another $2,000+ into another piston operated gun would seem to fit Albert Einstein's definition of insanity; "Doing the same thing over and over and expecting different results".

Even with a piston operated system that runs completely flawlessly, I see no advantage that is worth the extra coin.
 
Re: DI vs Piston for .308 AR?

I honestly never believed most of the hype put out by some of the piston manufacturers such as the gay ass videos of the guys popping out of the water or touching the BCG after a mag dump. What I like is how much cleaner they are. I got tired of cleaning. Sorry that you had a bad experience with yours. Mine is one of the smoothest shooting ARs I've ever owned and very accurate.
 
Re: DI vs Piston for .308 AR?

Paulosantos, I really am glad to hear that you are having good luck with your gun, it gives me faith in that company. I know that they do make quality stuff. Perhaps I got a lemon, but I really did not benefit from the GP system.

By the way my favorite video is when the bury the GP gun in the sand (magazine inserted and ejection port cover closed), pull it out the sand, and dump a mag. I'm pretty sure any gun will stand up to that kind of "abuse".
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body">Paulosantos, I really am glad to hear that you are having good luck with your gun, it gives me faith in that company. I know that they do make quality stuff. Perhaps I got a lemon, but I really did not benefit from the GP system.

By the way my favorite video is when the bury the GP gun in the sand (magazine inserted and ejection port cover closed), pull it out the sand, and dump a mag. I'm pretty sure any gun will stand up to that kind of "abuse". </div></div>

LOL. I remember those videos.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: oneshot onekill</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jakhamr81</div><div class="ubbcode-body">I jumped on the "gotta have a piston operated" bandwagon (in 5.56), and I am now off that wagon. Yeah it's neat to dump a 30 round mag as fast as you can, and pull the bolt out to see how cool it is, but that's about it. Their really isn't an advantage to going piston. does the bolt stay cleaner sure; what's the trade off? You might end up with an unreliable system that has signs of carrier tilt and consistently malfunctions. The bolt carrier groups can get very dirty and still run flawlessly, just keep the parts well lubed. Stick with DI gas. </div></div>
I'm curious... Have you ever seen a piston AR fail or become less reliable because of "carrier tilt"? Do you even know what it is? I've personally seen over 10,000 rounds run thru a piston AR. Yes, there were signs of "carrier tilt". Did the AR function any less reliably because of "carrier tilt"?... NO. Carrier-tilt, by virtue of physics, reaches a certain point with regard to wear and then ceases to wear the rifle any further... Long before any "real" damage is done.
It's been my experience, after having actually fired tens of thousands and maybe even hundreds of thousands of rounds thru both systems (mostly DI) that the DI system fails far more often... Because of the way it operates.
Oh, by the way, you're right about the inside of the "suppressed" piston gun. It does get just as filthy as a DI gun. Just does it less quickly. </div></div>

Here is what happened to my receiver extension from what I would call carrier tilt; and yes it did cause malfunctions. From what I could tell the bolt carrier group grinding into the the receiver extension slowed the BCG down enough that I could actually feel it cycling (very sluggish). The BCG had a tendency to get hung up on my magazine. Slapping the bottom of the magazine usually cleared this malfunctions.


P1020224.jpg


I don't doubt that you or anyone as fired thousands of rounds from different gas piston systems without major hick ups. For me on the other hand, am at a 100% failure rate for gas piston operated ARs (This was my first and last). Including all of my issued weapons, I have had well over 20 DI gas operated ARs, M16s, and M4s, and I cannot say I had any problems that were directly related to the gas impingement system or the BCG getting to hot or dirty. A little bit of maintenance has always kept them functioning properly. The DI system is a well proven design to me that I will be sticking with. </div></div>
Yea... That's definitely some significant damage. Do you mind me asking which Piston Gun that is? I've seen that on the Ruger and some guns that were converted to Piston with either an Adams or other kit. The problem with the piston kits is that you often use your existing BCG. The ones designed for piston AR's are fatter and beveled in the rear to keep from digging into your buffer tube. Like this:
2m34w41.jpg

I'm not sure why the Rugers tear up buffer tubes but it looks like your buffer tube was designed to engage the edge of the pin one-turn-early. I've had buffer tubes like that too. I notched the bottom of the tube deeper so I could get another turn or two and have plenty of buffer tube to cradle the BCG. Like this:
2e2ieds.jpg

The scuffs you see are from my lack of dremel-fu.
 
Re: DI vs Piston for .308 AR?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bmt</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hopps</div><div class="ubbcode-body">Adverse conditions...like a firefight in a dust chamber?

</div></div>

Frozen Chosin?</div></div>

Pretty sure if you use a lube rated for sub zero temperatures either system will function; so that's not it.