which do you prefer in an AR platform? I won't say better or worse since each does something better and worse than the other
Piston or DI in an AR
which do you prefer in an AR platform? I won't say better or worse since each does something better and worse than the other
I am an ignoramus on this subject. What are their quality, in comparison? I only ever experienced the Coke Classic of the two
generally
DI
>less mechanically complex
>lighter weight
>smoother recoil impulse
Piston
>more readily tunable gas settings, especially for suppressor use
>certain adverse conditions (like shooting after coming out of water) are possible
>less carbon in operating parts and being shot out of the ejection port, which is a carcinogen (Estonias rifle contract specifically cited this as a factor for wanting an external piston)
Reliability is about the same in "normal" conditions for DI and a well made piston system like an LMT or PWS. Meme tests like the in range mud or Garand thumb don't count as those conditions are beyond even mil spec solicitation autism.
Im of the opinion that a DI system is more durable too. You're not gonna crack pistons or bolt carriers on a DI gun. (And yes it does happen, Im pretty sure Matt from Demo Ranches MP7 had the bolt carrier crack where the piston was hitting it)
>>less carbon in operating parts and being shot out of the ejection port
Any AK guy knows how false that is
>in an AR
kalashBlack folk need not apply, that overgassed riveted together piece of communist shit is the most overrated gun in history
>50 yr old dug up AKMs are still dropping bodies all over the world
Lol. Lmfao even.
Yeah but AKs are overgassed as all frick, piston guns in general need not be. I don't get gassed remotely as hard shooting my SLR.
DI is inherently more accurate and inherently more durable.
With a piston system you have an up/down rocking force affecting the recoil and rocking the bolt up and down, this causes wear similar to how an engine piston "ovals" the cylinder as time goes on.
Is it serious? No, just like a vehicle engine that can last multiple hundreds of thousands of miles a piston rifle will last many many thousands of rounds.
The accuracy effect is very real though - I would make a hard statement that no equal quality piston action could ever be as accurate as an equal quality DI.
I forget the video but someone explained how Stoner's DI is more technically "piston in bolt" and it made a lot of sense.
>I forget the video but someone explained how Stoner's DI is more technically "piston in bolt" and it made a lot of sense.
hell ya brudda, DI is just an extra-short-stroke piston
I mean, the shortest long stroke you ever short longeded...
who even cares, every system has gas make bolt go ka-chunk so you can make bang again, they're all fine, rifle is fine, give wodka plz
dunno how you wouldn't have a cantilever force on a DI bolt just the same. the force is on the top of the bolt, but the center of mass is below that point, so it's going to try to push the front up and the rear down.
>the force is on the top of the bolt
It's not, though. Most of the force is directly on the centerline, between the back of the bolt and the inside of the bolt carrier. There's still some force at the top, where the gas key telescopes over the gas tube, but because this is much smaller area than the area of the bolt shank, it contributes a small fraction (about 13%) of the total force.
The center of mass is also above the geometric centerline, thanks to the gas key on top, and magazine lip cuts below. I'm not certain if the center of mass is raised exactly the right amount to balance the gas key's force contribution, but it certainly makes it better.
if you think the force is at the gas key you're wrong. the force which throws the bolt carrier group to the rear is almost entirely generated behind the bolt through pressure*area. the bcg jumps off the breech kind of like a pneumetic tamper.
the piston system is generally heavier and poorly regulated so it generates more recoil.
the DI system sends more shit back into the action of the gun.
depends on the piston, things like PWS or the LWRC system vent a lot of the excess gas and the main complain is really weight
my AR is DI. the forces all being in line is mechanically elegant. brutishly hitting the BCG with a piston works, too.
Purely for suppression, long stroke piston. It keeps gas and maintenance to a minimum. Anything else, just roll with a normal AR.
PWS Chad is that you?
You know it. PWS mk116+ griffin m4sdii is my main rifle. It is impossible to get gassed out at any firing rate and the mags are practically spotless compared to the Stoner system suppressed
based, I have a MK116 Pro I got during the closeout sales and the thing is immaculate
Love the pros. The thicker 6061 aluminum is no factor compared to the 7075 and is so much lighter. The chunky machining is a vibe
my only issue was that the cam pin was gouging the shit out of the upper, I'm assuming due to the 6061 being softer. I dropped in a roller cam pin and it cycles smooth as baby shit now
That's the only thing to watch out for. Other than that, they're flawless. Put a can on it if you haven't yet. It'll quickly be your favorite rifle to shoot.
had similar concerns and actually spoke to someone at pws about it. i had a groove worn in my thing, and they basically said "yeah it is going to do that, but it's not like it's going to wear a hole clean through the upper". after a couple thousand rounds, all the wearing that is going to happen, will have happened.
fair point, but I have it on an ambi lower and it seemed like it would get choked up if I used the ambi bolt release. Putting the new roller cam in made it work perfectly
I have a piston AR-style rifle, but I haven't really shot DI AR much to compare. I will confirm what others have said: I ran 400 rounds through my rifle and the chamber area was barely dirty.
i think piston is theoretically better but the difference will probably never affect you unless you're running some very eccentric setup.
it's probably better to go with what is standard, for the sake of ease of access to parts.
i've got a pws upper and it does feel different but short of getting gassed out i've never been all that inconvenienced by a DI gun.
I had this conversation with a buddy and we concluded that for recreational/larping use DI is overall better but for widely issued military rifles piston rifles are superior
D-I due to parts and standards. You can just about "Lego" a D-I AR together, but the piston offerings are still too brand isolated in what you can get.
If you were running a can a LOT with a shorter tube, then a piston upper can make sense, but otherwise stick with D-I. (Or blowback if you have to have a pistol caliber AR)
superlative makes probably the best "drop-in" system today when it comes to pistons, enough so that a few companies that sell piston rifles just use their piston kit
Looks like an evolution and/or improvement of the old "Rhino" system. (which looked janky but worked fairly well)
It'd be nice if makers just standardized on a pattern. If Colt ever really unfricks itself, an offering of the old 703 would probably sell well.
POF already perfected it. They added a solid block of metal between the op rod and gas block so the rod doesnt deform under the heat of full auto firing. Plenty of bent rods on the forums about superlative's piston
Good to hear, I remember when they were still working on it, but I never really followed up on where the system went. Had the chance to shoot the shit with their owners a few times at the SAR show (the machine shop I worked for was a NFA manufacturer), and while I'm not very interested in a piston AR, I do recognize that in a few applications it has some advantage, and there is definitely a market for it.
POF’s isnt a drop in system dude.
Colt had their articulating piston which was actually a really good design, wouldn't be surprised if CZolt brought it back
I had a pof p415. It was magical. Handguard never got hot when im mag dumping. Decent suppressor host but the dinging it made everytime i shot it was too much. Oprods are trash
Has anyone ever figured out a short stroke system that allows A1/A2/CAR/M4 handguards, and keeps the FSB?
you could probably do a faux dissipator style build where the FSB is just screwed on and the gas piston (superlative probably) is underneath
I have a PWS long-stroke piston system with the enhanced buffer tube as a standard in the lower meaning it has an extended lower lip to prevent carrier tilt. Upper is Mod 1-M while lower is Mod 2-M.
I love it. It is easier to clean and the recoil is just fine.
yeah PWS stuff is the best piston on the market IMO
Idk...I like my LMT with a piston and DI.
how is the LMT piston? I know they're good but I haven't shot them firsthand
Pretty solid. I have the MRP upper so I can shoot DI and swap to piston just by loosening 2 screws, pulling out the barrel and swapping bcg. The bcg is like 400 and about the same for a piston barrel. So expensive if this is a route you want to go. I'm able to shoot my DI a little more accurately than the piston set up at the moment. It really shines with a can.
that's what I figured, it is cool that LMT offers that ease of changing out the innards of the upper
>unsuppressed?
DI all the way, don't frick with what ain't broke
>suppressed?
piston, please, for the love of god. short stroke, long stroke, I don't even care, just get that DI gas out of my face already
>picrel
Whatever they use for PAP AKs. My PAP M85pv shoots and you dont feel anything the spring just catches all the force if it had a full stock it would be my best gun.
I have mad respect for Stoner's system, but we need to acknowledge that it's mostly useless for 5.56mm. The cartridge simply doesn't have enough recoil for it to matter. Unsurprisingly, Stoner never used that system again because all his other guns were in 5.56.
Suppressors are only getting more ubiquitous and cheaper, so you might as well get a piston gun to be able to effectively use one.