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.
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.