i havent shot one or done enough research to justify the purchase.
my DI ar15s have given me no problems as of yet.
As 16" guns, I dont see the benefit of a piston.
SBR’s and suppressed weapons is where piston guns really work their magic.
this comes up often enough that I’ve been chipping away at an article for my website. Here it is in it’s current form.
Why Not a Piston AR?
From time to time people ask me my opinion of which piston-operated AR-pattern rifle they should by. Many are surprised when I reply with “none”. Inevitably the followup question is “why not?” This page is an attempt to answer that question. Be aware, these are my opinions based on my use and my experience with ARs both direct impingement and piston-operated.
Carrier tilt. In a DI gun the gas is routed through the carrier and expands inside pushing back against the bolt to unlock the action. This means that it’s pushing right along the center-line of the bolt and carrier as the carrier is pushed back into the receiver extension against the buffer and spring. In a piston gun the pressure is on the key, which is off-axis and which causes the tail end of the carrier to tilt down. This means that it rubs, or can rub, on the receiver extension where it meets up with the lower receiver. There have been some reports of pretty extensive wear in this area after only a couple of thousand rounds. AKs and other guns that are designed to run with a piston don’t have this problem because the bolt/carrier rides on rails and can’t tilt.
Proprietary parts. There is no standard for a piston system in an AR. If I need a gas tube for my DI guns I can buy one from any number of manufacturers. If a piston-specific part breaks, it’s sole-source and only the OEM maker can supply replacements. This is a problem both in the obvious short term if I need a spare part, and in a future with any potential ban or an unstable economy. Is a company who’s only product is a potential target for legislation going to survive a ban? Is a niche boutique maker going to survive a down economy? and if they go out of business, where do I get that part?
Incremental improvement. For the most part, the only thing that the piston makers are addressing is the operating system. I think this is a cop out, although I understand why they are doing it (the quest to get a government contract wherein the purchaser doesn’t have to buy a whole new gun but only a new complete upper). If I was going to go with a piston system, I’d like to see other improvements to the overall design of the system (lighter weight, integral rail systems, ambidextrous controls, folding adjustable stock, etc.). Frankly, I’d prefer to see it in a bigger/better caliber like the 6.8 as well, but then you get into ammo cost issues for training.
Turd polishing. Many of the piston systems are simply add-on, drop-in, or bolt-on to a standard or existing AR. What this means is that whatever parts were used to manufacture the host gun are still present in the piston gun, and may be us suspect quality. Even if a piston-operated AR-pattern rifle is the best thing ever, if the rest of the parts in the gun are suspect then it really doesn’t matter much. To be sure, it is possible to exceed the standards that the US Government uses in procuring their rifles and carbines, and many of those standards don’t apply to piston-operated guns, but if a given manufacturer can’t clearly state what standards they meet and what standards they exceed (and WHY and HOW their gun exceeds those standards) then they should be considered suspect at best.
Weight. A piston-operated AR is going to weigh more than a direct impingement gun. A piston and operating rod are heavier than a hollow gas tube. No matter what a maker of a piston gun does to lighten their overall package the same things could be done to a direct impingement gun and it would then be lighter still. The location of the extra weight matters as well, and the fact that it is concentrated over the barrel, and therefore only the support hand, which negatively affects the balance of the rifle or carbine. Even when comparing apples:apples and looking at a piston-operated carbine that shares the same outward appearance of the military M4 (plastic handguards, M4 stock, A2 grip, flattop upper, standard front sight base, etc.) the piston gun will weigh more.
Cost. Piston-operated AR-pattern rifles cost more than direct impingement rifles, often giving you a reduced quality of other parts, or parts you don’t want, in the process. Even when comparing apples:apples and looking at a piston-operated carbine that shares the same outward appearance of the military M4 (plastic handguards, M4 stock, A2 grip, flattop upper, standard front sight base, etc.) the piston gun will cost more.
??) Why? Much hay is made by the proponents of piston-operated AR-pattern firearms over a test, or series of tests, that the US military conducted pitting piston-operated systems against the standard M4 in which the piston-operated guns ran longer, dirtier, and without (or with less) lube. When I say “longer”, I am talking about thousands of rounds. Mike Pannone, a well-known Subject Matter Expert on the AR system, conducted a test where he ran a BCM M4-pattern carbine for 2,400 rounds without lube and without cleaning. Just think of how long it could run with a regular application of lube. Pat Rogers has direct impingement guns from Colt and BCM that he has run for tens of thousands of rounds without cleaning and with only a regular application of lube. If a direct impingement gun can be run this way then what, exactly, is the benefit of the gas piston system? What is it accomplishing given all that it gives up?
Now, I’ll admit to a bias. I’ve been successfully, and reliably, running direct impingement AR-pattern carbines for a decade. I routinely run these guns for over a thousand rounds of cheap, low-quality, dirty, steel cased Wolf ammunition. I most often wind up cleaning them out of boredom or curiosity more than any need to due to malfunctions or stoppages. Given that, and all of the above, I am reluctant to mess with success. I don’t begrudge anyone their use of a piston-operated AR-pattern rifle or carbine, I just don’t see any reason to pay more money for a heavier gun with a new set of reliability and wear problems and which may have a part fail that is difficult (if not impossible) to replace. But I am not a safe-stuffer, I am not a collector, and I lost that “gee wow” feeling when looking at a new gun a long time ago. Whatever is left lingering of that feeling is pretty easily managed by gun shows and other shooters I encounter on the range.
All my ars are di, but I will admit I think piston is better. I honestly just refuse to pay 2 grand for an ar though. When pistons come down, I am going all in!
Which companies are currently maufacturing piston guns ? I believe Ruger’s AR is piston driven, any others ?
Opinions on the Ruger ?
D.W.
I currently have an Adams Arms Piston system w/ Adams Arms one piece carrier and a DI “truck gun”. I had the Adams Arms guns built for me, carrier tilt was starting until I got the one piece carrier, no signs of it now. Both systems are good, but when it comes to cleaning, the piston is cleaner in the upper area, not in the rail area and runs almost cold, compared to the DI. The DI gun gets hot in the upper area. The DI gun needs more lube at the range than the Adams Arms one. I find cleaning the bolt on the DI is alot tougher. Weight is very close depending on what else you add to your guns (optics,lights, and other add ons). Both have very few problems with each having 5k to 10k rds fired. I would trust my life to either rifle at this point. Both are good, but do you need a piston? No. If you want it, go for it. I did and I’m happy with both rifles.
The biggest advantage to a piston gun is that it requires less cleaning.
How much trouble is it to wipe down a bolt and carrier?
A BCM 14.5" DI gun was torture tested with no lube and ran for over 2,000 rounds.
Google Ruger SR-556 carrier tilt
The following companies are established in piston AR market and do not offer DI guns: HK416/MR223 (not yet available to US civilian market), LWRCI, and POF. All of these are acceptable quality for a class. The HK platform has done well in military circles. Pat Rogers did a good chronicle of the LWRCI M6 platform about a year ago. I’m not familiar with any high round-count testing of the POF.
The following companies offer piston variations: LMT (MRP), Adam Arms, Bushmaster, Spikes Tactical. I’d only be comfortable with one or two of these in a class…
The Rugar offering is a relatively new player. I’d stick to one of the big 3 based on initial reports on this system.
FYI, I did not invest in piston platforms (all suppressed SBR) until I had a solid stable of DI guns with plenty of spare parts.
Here.
I’d say they’re worth it if you’re doing any 2 of the folowing 3 things: SBR, full-auto, running a can.
If you’re not doing any 2 of the 3, you’re spending 30- 60% more for a gun that doesn’t do anything a DI gun can’t do just as well.
Im sorry but unless you’re running a suppressed SBR you have no right to even reference how “dirty” your AR gets.
Unless you’re dropping the thing in mud or LIVING in the freaking desert and firing thousands upon thousands of rounds lubing the gun will keep it running for an amazing amount of rounds.
IF you’re properly lubing cleanup is an absolute breeze. Simply strip the carrier, wipe it down, relube. Run a boresnake down the barrel, clean your chamber with a chamber brush if you want, reassemble and shoot some more.
Excessive cleaning came about for two reasons.
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Indoctrination in the military saying that your weapon must be tip top, spit polished at all times (this is not necessarily a bad thing).
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Anal retentive couch commandos that have never pushed their weapon system to see what it can do. They buy into whatever is pushed in front of them and stick to it like its their last bastion of hope.
Im an anal retentive couch commando but i have the luxury of NOT having my life on the line when i go to the range, therefor i can push my equipment and myself to failure.
Y’know, not for nothing but we civis are a lazy ass bunch. Like i said before we have the luxury of NOT being in harms way. If our shit breaks, it breaks, we step off of the firing line and fix it. For all of the information out there on the vast interweb, 99% of it is worthless. Such a shame, i wish more people were contributing FACTUAL information based upon their findings such as 87GN and Rob_S.
These kind of debates are all but worthless. If you want a piston, buy one, just dont come on here and tout how it fires LAV guided laserbeams and Costas flechette beard hairs.
*Note, no offense intended to the original poster as he was merely seeking to educate himself on a potential purchase but these threads come up far too often. Thankfully they’re relatively cordial on M4C as we seem to have far fewer fanatical cultists on these forums than some others…
Great points…and I agree with them all. Why no mention of accuracy in it though?
I agre with everything here except the excessive cleaning not being bad.
I dont find keeping an AR functionaly clean to be a hard task at all. it only takes a few minutes to wipe everything down and lube. Thats how we cleaned our rifles in the field and in the sandbox when I was in.
But when we got back to the barracks the 1st Sgt wanted the rifles to be SPOTLESS. You couldnt keep oil on them when you turned it in, because the oil would pull out microscopic amounts of carbon and turn blackish and the 1st Sgt would say its dirty.
So most soldiers would scrape the shit out of the internals of their rifles and then make sure it was dry as a bone before turning them in. We would literally spend days cleaning weapons before turn in.
IMHO no they are not.
Most would be better off getting some info on knowing how to keep their DI AR running reliably. I rarely clean mine, just lube and shoot… and only after 3-4K rounds fired shooting 10s of thousands of rounds of Wolf and Barnaul over the years, and through Carbean courses, reliably. In a Pat Roger’s course, Pat had T&E DI AR’s (Bravocompanyusa ARs) well over 10K rounds fired, just lube. My T&E Middy had over 14K rounds and I only lubed it once (very well) during the 3 days with Slip EWL AND shooting Wolf, without any malfunctions. #14 (Filthy 14) had I believe, over 25K+ rounds fired with just lube.
IIRC, the majority of the malfunctions with the M-4 on the dust chamber test, were Mag related. So buy some quality Mags and Lube your AR generously.
Several reasons.
The biggest is that I’m not a benchrest shooter, and so I not only don’t CARE about the minute difference that may exist in accuracy between the two I am also unqualified to talk about it.
I also frankly think that many people that talk accuracy issues generally can’t hit the broad side of a barn. I’ve sat at the range and listened to two guys discuss the various merits of this and that only to bring their target back looking like it’s been peppered with buckshot not shot with 5.56.
I hear you…been there done that …but, Excessive Boot camp/parade inspection cleaning has worn out more weapons and caused more damage, than the actual usage of the firearm.
Most weapons are more accurate that the owner. If this was a competition forum, MOA would be all the rage and not cleaning would be sacrilegious. You’d be very surprised at how many military shooting teams, that don’t clean their match grade weapons, until after the shooting season and well after thousands of rounds fired. A fouled barrel allows you to track your shots and provides consistency in shot placement. If you clean it, you just screwed your zero and range book.
The only logical reason to go with a piston AR is if your running a SBR suppressed. Even then it isn’t a big deal. There is absolutely no benefit otherwise, and a plethora of negatives. People just love the snake oil though :rolleyes:
This may sound ridiculous to some, but I just can’t get past the fact that Gene Stoner didn’t design it that way. The piston system has been around forever, and yet here we are all shooting various brands of the same rifle. The inherent design has survived this long and proven itself. It’s hard to beat this track record.
I’m with everyone that says that DI is the way to go still. Unless piston prices drop to almost DI levels, I don’t see the need. Ofcourse, most people spend money according to their feelings and emotions so the level of need is less of a factor. For me, a no nonsense DI is just fine. Especially since I’m not using it for battle. Like Clint Smith once said, the most he’s ever heard of someone shooting through their rifle during battle was less than 20 mags during a period of over an hour. I don’t think my 10/22 will have a problem shooting 600 rounds over the course of an hour.
Some DI torture tests.
Myth of “Fouling caused by the direct impingement gas system makes the M4 Carbine unreliable.”
http://www.defensereview.com/the-big-m4-myth-fouling-caused-by-the-direct-impingement-gas-system-makes-the-m4-unreliable/
Bolt lug cracks at 16,400 rounds. Replaced and continued until 3 FTE at 26,450. That’s when they decided to clean it.
http://www.03designgroup.com/reviews/bcm-complete-ar15-upper-and-lower-receivers