Complete ignorance here- are there any?
I just don’t understand the fascination with a more complex, heavier system of operation. Especially since there are about 10 different versions- which get discontinued etc…Good luck find parts for that in 10 years. It’s never made any sense to me. DI works very well. The only reason I could think of to do anything else would be some real evidence that somehow piston guns are more reliable, but I’m not aware of any real studies that show that.
DI in a quality gun has always been a proven design. I don’t understand the fascination with piston driven ARs either. I get what they are trying to say about less blowback into the action but a quality DI gun that’s well maintained (as any serious defensive gun should be) is the way to go in my humble opinion.
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I wanna say there was a study done around the time of the SCAR program that includes the HK416. So I think there is info regarding it. However that’s more just a study of the 416 vs the M16/M4 and not a piston vs DI thing.
I’ve always just owned DI guns, shot them a ton but never in any harsh environments if you will. I could see the argument for something that be able to run through dirty/harsh environments on an autoloading firearm. The classic scenario I think of when I hear about complaints about DI guns not running when in dirty/harsh environments is the M4 out in the sandbox but I don’t know how well some of those rifles were maintained either but then again I was never there so that’s just a thought. One thing I’m curious about on a piston driven platform since I’ve never owned a piston driven AR is how much carbon buildup actually builds up in the piston and how often that has to be cleaned/maintained?
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Probably thinking about the “dust tests”
https://www.military.com/defensetech/2007/12/17/m4-comes-in-last-place-in-dust-test
I think the only AR-pattern op rod that has a case for it is the 416 and most of that context is in relationship to the 10.4" DI variants of the day. And as some may remember, the HK was not without some teething/production issues and has enjoyed several production improvements along the way.
In the context of today’s knowledge, it has been surmised by industry types that perhaps a significant portion of the HK’s success may not be due to the op rod but just in the use of different materials, alloys and their otherwise German approach to the AR platform…
I think one is hard-pressed to find a simple cut-and-dry answer given that context and cost are always going to be a factor. I do believe that in certain roles, configurations and environments, there are advantages to the 416 op rod IF one insists on having an AR pattern gun.
I don’t know of any studies (maybe one related to the HK piston AR’s??), but I remember reading in some gun rags of the late 70’s and 80’s how the heavier and cleaner BCG of the AK made them SO much more reliable than the unreliable and whispy M16. So the idea of converting AR’s to pistons I believe started there. The total piece of junk “RHINO” system of the day was the first attempt at a piston conversion that I’m aware of. I guess some people through the decades just couldn’t let the idea go.
If you run suppressed there is definitely a case to be made that they run cleaner than a DI gun. Also less gas to the face. I wanted a PWS in the worst way until I picked one up and the added weight was noticeable. It’s hard to argue with the design. A couple billion AKs are still out there running strong.
Certainly, there was no bias or propaganda from them days…no sir. It was well into the 90’s and 2000’s that most folks still believed the AR pattern was crap and would seize up at the drop of a hat and the AK was an indestructible force of nature that an untrained chimp could operate in the harshest climates that would kill mortal man.
Long before the days of the reality: “The AR is more reliable that it gets credit for, and the AK is more accurate than it gets credit for”.
All that being said, I’m not so sure the AR18 pattern stuff isn’t going to be the best vehicle for a small-frame semi-auto carbine once it gets its due development time (if that ever happens given the state of things)
The largest problem is that reports are often setup to reveal the info the researcher wants. You want DI to win, ok, easy. You want piston to win? Ok, easy.
If you want to see ugly back door politics and money at play, dig into weapon testing and / or supplying military arms.
https://en.wikipedia.org/wiki/The_Pentagon_Wars
I still like Piston for suppression and full auto fire, other than that, I don’t see a point.
Outcome driven research. I think the bigger issue is that people consume reports like these and regurgitate them as being gospel. No critical thinking ability. I blame the interwebs.
I have a single piston AR, a 16" PWS Mod 2 which weighs 6.5 lbs, right in line with my other 16" DI rifles. The long stroke piston design gives it the same number of moving parts as DI, and it does have the benefit of less gas and sound to the shooter when shooting suppressed. Actually very pleased with it, and thinking of picking up one of their 11.9" uppers for a suppressed pistol build.
I can’t really speak to overall reliability as I haven’t any issues with any of my rifles, thankfully.
I’d trust a study showing reliability on a piston AR about as much as I trust the CDC or World Health Organization. :stop:
(Wait! Dr Fauci has a piston study coming out!)
piston ARs are either novelty or special use. i dont really think of them as ARs, myself, and dont compare them to DI rifles in my own mind - they arent ARs. theyre heavily modified ARs. and since i like the DI design, dont shoot suppressed, i have no use for them.
as to which is more reliable… boy i just dont think thats a question worth asking. there are far, far, far too many variables - too many if/then questions/answers to ask and answer before we can make anything close to a strong apples-to-oranges comparison and say with any degree of certainty that any particular family of piston designs is or isnt more reliable than DI.
if you would benefit from a piston AR, you already know it and can make that call, methinx. for everyone else, DI is the starting point.
There is an excellent discussion of the reliability of the HK416 in P&S Modcast 100 on YouTube. https://www.youtube.com/watch?v=pyYODtiohzQ&t=3849s Around the 50 minute or so mark, Chuck Pressburg goes into discussion of the 9 years he was deployed in Irag and/or Afghanistan as a member of an elite special forces group. Had virtually no malfunctions and never cleaned his weapon during the entire time he was deployed. He is a big HK416 fan, as you can imagine. Not a test but a real life experience with the HK416. Personally, I own a bunch of piston rifles (HK416/556, Sig 516, Sig MCX Virtus) and also several DI rifles (Centurion Arms all). They all shoot well, but if I had to choose, I’m taking the 416/556 every day of the week.
HK put the infomercial out of a 416 vs. an M4 and one of the demos was pulling both out of water and firing immediately that resulted in the Colt barrel bursting while the 416. If I recall right, it was at least implied that the difference was the piston, but the 416 barrel is cold hammer forged(which I have read a few places are more burst resistant than traditional barrels).
Anyone seen any testing as to piston giving that result versus barrel manufacturing process?
That is a feature with the HK that has support inside the chamber called OTB (over the beach). The Sig 516 (designed by the same engineer that was responsible for the HK 416) has the same feature. There is no doubt that the 416, and to some degree, the 516, are grossly over engineered compared to a normal M4
As I recall, Colt sued over that demo and showed that while the HK was pointed down to drain and given about a second longer to do so, the M4’s barrel was slightly pointed up and fired without any such delay.
Honestly I don’t get what the big deal is. Assuming neither version is slapped together from airsoft parts get whichever, both work fine
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Yep both do work fine.
I own HK piston rifles and they are excellent. I also own DI AR’s and they are also excellent.
The biggest advantage to my HK piston rifles is how easy they are to clean.
You don’t get any carbon fouling beyond the tappet piston. The bolt stays pristine, which isn’t the case with my DI rifles.