What advantages does short-stroke piston have over direct impingement?
What are the disadvantages?
The first makes makes my dick hard. The other is more economical.
>>29456959
Direct impingement makes your receiver dirty and could very well end up spewing powder residue and muck into your magazine. It will require more maintenance to be a reliable platform.
A short-stroke piston will have all the gasses and heat pushing halfway down the barrel, removing any extra stress on the bolt and receiver. This platform is, in many cases, more reliable if you intend on dumping mag after mag.
There are advantages and disadvantages to both. Direct impingement systems are generally lighter in weight too..
>spewing powder residue and muck into your magazine
>extra stress on the bolt and receiver
>1963+53
>still repeating disproven garbage
>>29457013
I can only speak from personal experience. Feel free to take it any way you prefer, it doesn't really matter to me.
>>29457020
In my experience, I've had far more failures on Soviet AKMs than M16s or M4s. I also found an AMD-65 that had to be kicked in and out of battery and constantly failed to feed, chamber, lock, unlock, extract and eject. Once it was in battery, I never had a fail-to-fire, though, so I guess it had that going for it.
>>29456959
Advantages: Cleaner and more reliable because of less heat and carbon fouling in the heart of the system. Therefore also less wear and tear. More potential for higher rates of fire. Easily over-the-beach capable. Easier to make short barreled rifles with.
Disadvantages: Slightly more complex. Needs a bit more engineering thought to get it right.
DI fucking sucks. There's a reason no modern firearm uses it (with the exception of the Desert Eagle)
>>29457074
To add on to the others' disadvantages
Weight. Piston rifles tend to be heavier, but that has more to do with the lightweight of the DI system.
Heat. All the heat and shit goes out through the front, which arguably makes it more reliable, but also makes the front-end get really fuckin hot much faster than an DI
Cost doesn't necessarily have to be higher, but given the state of things piston guns have a bad advantage:cost ratio.
>>29457085
>lightweight
light weight. Two words.
Advantage is that you don't get carbon build up in the chamber which makes it more reliable.
Disadvantage is more moving parts which makes it harder to clean and maintain.
>>29457142
Got an LWRC piston in 556 and syrac piston 6.8 w/ form 1 can, also a few DI. IMO either is fine. I like the pistons better with a can, and makes cleanup a breeze. DI makes a shitty mess but most people dont shoot enough in one sitting to foul enough to jam. Really more of a personal choice but im going with pistons from now on.
>>29457142
>>29457144
this is broscience
piston system chamber experience no significant difference in carbon build up from that of DI system chambers
this of course is due to the DI system on an AR doesn't have anything to do with directing the gases into the chamber at all.
>>29456959
They break alot more than DI AR's and also cause the bolt carrier to tilt.
>>29457142
This carbon buildup is marketing bullshit pls stop
>>29457085
>weight
The weight difference in the gasblock of a short-stroke piston AR isn't even noticeable. It's a few ounces difference in the decent designs.
>heat
Yeah, no. They both get hot during rapid fire because it's the barrel that's really soaking up the heat.
Pretty much, your post should have just been "the companies that do piston AR best are damn expensive for basically moving the crap from the bolt carrier to the piston face."
>>29457040
IO inc garbage ā Soviet akm
None
>>29456959
zero advantages
creates more problems by putting in a system designed for a railed bolt carrier on one that has no rails.
>>29457244
>also cause the bolt carrier to tilt
Wearing in the buffer tube isn't a big deal as long as the carrier always cycled properly. "Carrier tilt" is just a boogey man the piston AR companies use to make their piston ARs look better than the competitors. The gun can handle it. For fuck's sake, the charging handle "tilts" the carrier, but you can yank on that until it breaks and the gun wouldn't care when you fire it.
It's completely unnecessary but more pretentious so it makes people feel better
>>29457278
pistons in ar rifles are shit and you know it
>>29457278
>carrier tilt is a boogeyman
>carrier tilt only affects your buffer tube
enjoy your locking lugs peening and then your gun blowing up in your fucking face because it can't lock properly
>>29457040
HK MR223 (short-stroke piston) and Ruger Mini-14 (M14 type piston) model 5847 hasn't failed me yet, while Stag Arms 3T-M (direct impingement) has failed so often that it's not even fun to troubleshoot it anymore.
Now, I do realize that my experiences alone isn't representative of everybody else, which is why I only wanted to share my two cents.
>>29457278
This carrier tilt is bs these days
>>29457816
My stag 8T (piston) has never failed on me.
>>29457816
>Stag Arms
I don't think DI is the problem here.
>>29457977
For some retarded reason Daniel Defense rifles are restricted in Norway. Only semi-auto rifles I can legally own are:
1. Colt AR-15 H-bar/Sporter produsert etter 1986,
2. SIG SG 550 SP,
3. Steyr AUG sivil modell,
4. Valmet M76/78A2,
5. Galil AR,
6. HK-94,
7. Bushmaster mod. XM15,
8. Olympic Arms AR-15 H-bar,
9. Heckler & Koch modell SL 8,
10. DPMS Panther Bull 24/DPMS Panther Bull 24 Spesial (inkl. Ā«SouthpawĀ» mod),
11. Oberland Arms (OA) 15,
12. Izhmash Saiga sport 520,
13. Izhmash Saiga sport 555,
14. Tiger mod 03,
15. DPMS Panther mod LR-308 (inkl Ā«SouthpawĀ» mod),
16. Armalite AR 10,
17. Armalite AR 10T,
18. Arsenal SAR-M1,
19. Heckler & Koch MR 223,
20. Heckler & Koch MR 308,
21. JP Enterprise CTR-02,
22. Armalite M 15,
23. STAG 15,
24. Smith & Wesson M&P-15,
25. Benelli MR 1,
26. JP Enterprises LRP-07.
Then there's the matter of cost as well, which is why I didn't want to invest too heavily into my first AR15. Now that I have learned a bit, I figure I'll rather build one on my own based on a HERA upper and Bushmaster lower.
Sucks to live in Norway. We're not as free as you are :-)
>>29458037
Then again we dont tend to shoot up schools as much either.
>inb4 Swedish Ninja
>>29456959
In ARs, unless it HK or similar, is Much less reliable and contains many small and fragile parts. Mag dump is hard, period, but fear a piston breaking well before my rifle "dries up".
You know full and well if you're going to mag dump. If you do, shot of oil before and all my mags will work great.
>>29457977
What's wrong with Stag? Mine functions with brass in pmags all day.
Question for DI gun users: how much carbon build up is normal on the BCG, and how often do you actually HAVE to dissamble that stupid fucking cotter pin and clean the firing pin?
Question for piston gun users: how much wear have you seen on your buffer tube and how many rounds have you put through it?
>>29458345
AR-15's DI system doesn't work like traditional DI as the gas, carbon, and other shit doesn't hit the bolt face, rather right behind the bolt face.
My AR-15 has nearly 20k rounds through it, and besides general cleaning I've never had to unfuck my firing pin or do a super thorough cleaning of my bolt face.
>>29458345
Lwrc short stroke 10k rounds and another ~2k on my second barrel, original everything buffertube shows zero "carrier tilt" wear
>>29458345
I have both. I clean my DI AR after every range trip (~2-300 rounds) and it's jet black inside the carrier. It wipes away easily but I think it would still function well after a 1000 round trip.
My piston kit had a special bolt carrier with rounded pads in the back to prevent tilt erosion. The buffer tube inside bottom surfaces are slightly more shiny than my DI guns. I've put 1000 rounds total through it because it keeps jamming and can't be bothered to fix it when my DI rifle works better.
>>29458148
On this point, I want to see gun laws plotted against mental health care (not sure how to measure that) & spree shooters (without gang affiliations), that would be pretty educational to see
>>29458813
Why do I have a trip?
How to turn this off?
>>29457298
the force of the fucking firing pin spring isnt enough to cause peening from tilting, while the bolt is locked you fucking mongoloid.
carrier tilt is a meme, only relevant in ARs with shortened carrier, and probably shitty cheap ARs
piston guns are good in arctic conditions, you dont want DI that heats up more of the gun, and are more prone to locking up.
>>29458037
think someone are working on getting them approved. but just buy a DD upper, and put it on whatever lower from that list. only the lower receiver needs to be on that list.
>>29458822
now now regina, calm your tits. and check your date
having used the AG-3 and the Hk416 as my service weapons, and having had the pleasure of spending a lot of time on the range with the C7/C8 as well, i've noticed the following:
AG3 is by far the dirtiest weapon i've used, followed by the C7/C8 and then the Hk. I have no idea if the shit that builds up from firing more than a few thousand rounds without heavy cleaning will affect the weapons differently in any measurable way, but i'd take the Hk any day for less "how the fuck do i get this shit clean"-situations.
This is just my personal experience, might be completely wrong with regards to the bigger picture though.
Please someone post those images of the buffers shearing the fuck off because of misalligned shit in piston ar's
>>29459782
The hell is an AG-3? Canadian name for G3?
>>29460185
When you google it, literally the first result tells you it's the Norwegian designation for their licensed and domestically built G3A5 with a few modifications. Don't be lazy.
I just ran a google image search on "carrier tilt" from 2015-01-01 until today. This was the only image that came up that wasn't from a post before 2012.
He claims 13,000 rounds on an Adams Arms, but it's the internet and people never lie on there, right?
>>29460217
I did google it, that's how I figured it was some kind of G3.
>>29460353
Use better Google.
>>29460400
Mee nyt vittuun /_\
>>29460509
Jospa en.
>>29459782
downside of the roller delayed blowback.
but it can run alot dirtier than the hk. which has an issue, where gunk from the blanks gets in and fucks up the ejector pin. its a user error for not cleaning the gun properly after using blanks, the buildup was practically nonexistent with normal ammo.
the AG-3 on the other hand works kinda like the mg-3, its dirty as fuck and it likes to be run wet, which collects even more shit. but it works.
>>29456995
Memes: The Post.
>>29457142
>>29457144
This is a much better info graphic.
>>29458865
>firing pin spring
>in an AR
>>29458345
There are "DI" guns that are tens of thousands of rounds with no cleaning and just lubed that run fine.
>>29457040
Is this an argument against all pistons, or just long piston?
>>29456959
pistol systems in a AR are a meme system
![CIMG1080[1].jpg](https://i.imgur.com/ShAP7eN.jpg "CIMG1080[1].jpg")
>>29460610
>all ARs are the same
>>29460646
The amount of flex in that video is amazing, especially where the barrel meets the receiver. I'm beginning to see why people are putting out monolithic uppers.
>>29460651
>one special snow flake that is a G36 with a body kit.
>>29460918
I'm not following you there. I just image searched the G36 bolt carrier and this came up.
>>29460991
The short stroke gas piston on the 416 (and other small things like the firing pin spring) are carry overs from the G36. Obviously the bolt carrier is going to look different.
>>29457144
>>29457142
I know jack shit about guns (that's why I come here) but I'd like to add, after seeing these two side by side, that the direct impingement has to force the gas through a long passage, where it will loose a lot of pressure compared to the short stroke piston, which is an incompressible rod.
>>29458865
This kind of shitposting is exactly why I come here.
Listen up nogunz.
>bolt is locked into lugs, round in chamber
>firing pin smacks cartridge primer, boom
>piston flys back and smacks the top of the bolt carrier, torquing it downward
>as the bolt unlocks the torque makes the bolt lugs ride across the barrel lugs in a funny/crooked way and you get peening.
>so the bolt bounces backward peening on the barrel lugs and then smacks the buffer tube too, just for even more damage before riding back forward
![ar10[1].jpg](https://i.imgur.com/6RtsfKs.jpg "ar10[1].jpg")
>>29460918
>special snowflake.
its probably the on of the most common piston ARs there are.
also one of the originals used it too.
just drop it Holden, no matter how you twist it ARs have firing pin springs. and even without them the bolt wont be tilting when its locked
>>29460600
I wonder if you could modify the cam pin so the carrier torquing from the piston won't peen the bolt lugs.
Damn, I don't want shitty stupid piston AR-15s so I hope they don't fix it.
>>29461090
>things peening while locked
i know you're retarded due to liking piston ARs but at least try a little.
>>29460651
I wonder if that wedge shape on the 416 carrier uses the hammer to keep the ass end of the carrier from torquing down.
Wow that would be fucking stupid!
I bet those lowers wear out quick.
>>29458037
are mini-14s banned now because breivik used one to exterminate the next wave of white race traitor cuck politicians for norway
>>29461085
the forces on the lugs at the moment of unlocking is negligible. the forces the the bolt itself at that moment are tangential to the bore axis, untill its fully unlocked. not to mention a short stroke piston have shorter travel than what is needed to unlock the piston.
it is not a problem.
>>29461193
>i have no idea why cam pins sheer and locking lugs peen
this is why AR piston fags are retarded
>>29461157
its a safety feature melanie, it blocks the firing pin. get back in the kitchen
>german steel and aluiminium wearing out .
>ever
lauginhgirls.jpg
>>29461193
>the forces on the lugs at the moment of unlocking is negligible
If by that you mean every single pound of pressure the round is producing then sure.
AR-15s depend on the momentary injection of gas into the bolt piston to unlock properly.
>>29461231
not on piston ARs
>>29459782
>and having had the pleasure of spending a lot of time on the range with the C7/C8 as well,
What are you r thoughts on the C7/C8?
They dumped a lot of surplus C8 uppers on the Canadian market that were left overs from the Norway military purchase. They are pretty reasonably priced and I was thinking of grabbing one.
I hear people get pinched by that grenade launcher lug when they open up the gun for cleaning though. On the plus side the barrel is supposed to be pretty decent.
![normal_norsk_hjelm2[1].jpg](https://i.imgur.com/r5SS4g0.jpg "normal_norsk_hjelm2[1].jpg")
>>29461263
not that anon, I've only fired it a couple of times, borrowing it on the range.
pic is th eone i'ce shot 16inch "heavy" barrel
disassembly is just like any other AR.
and I have no idea whats up with the handguard on your pic
>>29461310
That is Colt's new IUR monolithic upper for the C7/C8.
The canadian forces are not using it yet as far as I know, but they did export a bunch of them to Norway. The ones sold here are milsurp.
>>29461105
What if you had 2 pistons and 2 gas ports, on opposing sides? That way they would cancel out each other's torque!
Plus, if one malfunctions the other might still have enough force to cycle, thus adding redundancy!
>>29461354
hmm if they did that recently they might just upgrade their old c8s instead of using the hk416s.
>>29461260
>>29461231
Could the stoner DI increase the chance of stuck casings, since the pressure forces the bolt forwards into battery while unlocking?
>>29461090
Just because one special snow flake has a firing pin spring does not mean ARs in general do.
>416 common
Motherfucker it wasn't available commercially until 3 or 4 years ago, and even then it is a neutered version
>>29461085
>>29461214
Different anon. Can you tell me if this is the correct sequence of events?
1. Bolt carrier moves forward, pushing a round into battery, and pressing the bolt up against the barrel extension and/or chamber.
2. The bolt pressing against the chamber causes the bolt and bolt carrier to move closer together. Due to the way the cam pin is assembled, this action forces the bolt to rotate. This moves the bolt lugs behind the barrel extension lugs, effectively locking the bolt in place.
3. After firing, gas enters the bolt carrier, pushing the bolt carrier backwards. (It would push the bolt forwards, but the bolt is already all the way forward against the chamber.) Again, due to the cam pin assembly, once the bolt carrier and bolt are moving apart, the bolt must rotate it's lugs out from behind the barrel extension lugs, allowing rearward travel of the entire bolt carrier group.
In both piston and DI guns, the cam pin assembly should receive some amount of force since it prevents the bolt carrier from flying backwards and leaving the bolt in place. Hence how cam pins sheer, correct?
Also, since piston guns have an impulse off the center of mass, the aft side of the bolt carrier drops, pushing the bolt upward. This could show faster wear on the upper lugs of the bolt and barrel extension, correct?
>>29461582
piston guns are missing the gas seal created by the DI rifle which times the unlocking and extracting cycle of operation. creating more pressure and premature unlocking through sheer force on the locking lugs and cam pin as well.
>>29461565
>Just because one special snow flake has a firing pin spring does not mean ARs in general do.
I've never said that. I responded to Bertha whom implied that ARs didnt have firing pin springs. when a piston AR that are in use by many armed forces around the world, which would make it one of the most common piston ARs
nobody gives a fuck whats common with american civillians if thats why you are considering it a special snowflake.
>>29461565
Half the firearms in the world are in this country. If it isn't common here, it isn't common.
>>29461612
>piston guns are missing the gas seal created by the DI rifle
what the fuck does that even means. they principle of operation is basically the same, its just that stoners DI use a more compact design with less parts.
and do you honestly believe that that almost same system are incabable of timing the unlocking.
>>29461713
American civilians have more guns than all the militaries of the world combined. No one give a fuck about special snowflake guns that come with million dollar support and logistics programs to instantly replace them when they destroy themselves.
>>29461612
The AR15, AR18, and G36 all use the same bolt lug locking design, correct? Is this issue mitigated at all in the AR18 and G36, or is it just another wear item in those rifles, like the cam pin?
>>29461731
Meant for
>>29461713
>>29461735
> More guns than all the militaries of the world
Going to have to call b.s. on that for 2 reasons: no source provided, and even if source provided, not all of those guns are DI AR-15s.
>>29461747
g36 and ar18 have the recoil spring in line with the piston, just like the ar15. this will only cause tilt because of momentum.
>>29461735
>no one gives a fuck about guns that provid multi million dollar contracts.
>>29461713
>a dozen or so militaries have a couple hundred for sf to use
Oh yeah, real fucking common Europoor
I wish I had the cash to spend on dirty ammo and pushing my ar to it's limits.
>>29461733
it means you don't understand how a gas piston works.
the gas seals the bolt and keeps it in place long enough for the bolt carrier to move rearward and begins unlocking the cam pin
the gas is exhausted through the exhaust ports on the bolt and out through the ejection port, the cam pin is still unlocking
with no gas seal to hold the bolt in the chamber the rearward force of the bolt carrier continues to the back of the receiver in a straight line, extraction begins and the cam pin is still unlocking
the bolt carrier is moving into the buffer tube and the bolt is fully unlocked and rotated to clear the chamber, ejection
a piston system says fuck all this dumb shit and just uses raw force to hamfist the bolt carrier group into unlocking and extraction.
>>29461759
27 million military personnel vs at least 80 million US gun owners
most of these militaries don't use the AR pattern rifle
>>29461784
norway alone has around 20k and more coming
>>29461873
>one country
>common
>>29461873
the US market moves 20k rifles in less than a month
>>29461878
arent you tired of moving the goalpost yet?
>>29461817
what you describe is similar to how a short stroke piston system work.
the difference being is that the DI has pressure pushing the bolt itself into battery during unlocking, untill the pressure is released. while the short stroke piston doesnt.
>>29461906
does it move 20k piston ARs in one month?
Honestly I would like to see some numbers of piston ARs produced
>>29461918
and then you ignore that last sentence of the post as you like the piston system hamfist your way into doing something.
>>29461955
hamfisting isnt necessarily bad Debra. and its preferred in arctic conditions.
>>29461193
Your understanding of mechanics is appalling. The piston induces a torque moment on the BCG and bolt.
The AR-18 design is designed to counteract this by placing the recoil spring in line with the piston.
Piston AR15 designs are retarded unless you want a 10" barrel. I don't know why people defend them for 14" barrels or longer.
>>29461975
>a gun destroying itself isn't necessarily bad
piston fags
>>29461790
Jesus H. Fuck that's dirty. I mean I don't go throwing my AR into the dirt if I can help it, but I've never seen one get that grimy and I shoot cheap shit too.
>>29461918
>its the most common piston AR, like so many countries use it guize
>no, a few have it for SF only and apparently one has it has standard issue recently
>moving the goal posts!
Meanwhile Ruger alone has sold over 28k SR556s and almost every AR maker in this country has a piston variant.
>>29462010
>ruger
>>29462010
>people sell shit to idiots
>this proves me right
>>29462016
Now whos moving the goal posts
>>29462023
Holy fuck piston fag.
>>29461222
Why wouldn't it have the same hammer retarder on the bottom of the carrier that all AR carriers have?
>>29462010
so you can consider the sr556 as possibly the most common piston AR, then how the hell is the 416 that has sold over 20k to on tiny country, considered special snowflake?
I dont have the excact numbers, but you are proving my point about the 416 being one of the most common piston ARs
>>29462051
>being a common piston AR
>same thing as being as common as the DI AR
>>29462051
Holy shit...
I didn't say it was the most common, only that it alone has sold more rifles than your example of Norway buying some. I get that your first language is made up shit no one else speaks, but I am using basic English.
>>29461817
So the bolt carrier is moving backward from the piston strike or gas expansion, but the bolt lugs are still behind the barrel extension lugs, the bolt stays locked in place, correct?
Since the bolt carrier and bolt are moving away from each other, the bolt begins rotating, unlocking. In either case, the unlocking process should be the same for pistons as DI, barring issues with carrier tilt wearing the top bolt lugs and buffer tube.
>>29462058
I've been talking about common piston ARs all along, of course the DI ARs are much more common than piston ARs alltogether.
so then the shitty ruger is also a special snowflake piston AR then?
whats the most common piston AR?
>>29462041
not familiar with the hammer retarder on other AR carriers.
but that thing is just a claw that holds the firing pin, untill the hammer lifts it up and the pin is "released" before the hammer hits it.
>>29462078
only if you completely ignore physics and the fact that there's a shit ton of back pressure from the round you just fired wanting to force the gun out of battery early.
>>29462121
isnt that pressure gone when the unlocking happens? if not the engineers should be put to the wall.
the DI system have that same pressure pushing the bolt back untill the gasses counter it, it doesnt happen instantly
Short stroke is shorter which means you can make your gun more shorter so it's useful in the hood.
>>29462121
I am not seeing how that is not occurring in either design. That back pressure exists in both designs well until the bullet passes the gas port in the barrel.
Assuming the same powder charge, DI or piston, the bolt lugs are forced into the barrel extension lugs with the exact same force until the bolt carrier begins moving backward from the gas pressure or piston strike.
All this and some part of me still wants an MCX. There is no help for my lizard brain...
>>29462178
is there anything wrong with it?
only problem with piston ARs are carrier tilt in shitty conversions. the mcx have the recoil spring inline with the piston so its not an issue.
>>29462201
Yes, it's not chambered in 6.5x39 like my video games said it would be.
>>29462065
you know the marines use the m27, right
>>29456995
>>29457020
>>29457142
>>29457144
I prefer to call you a liar and a shill for repeating such ignominious bullshit. Pic related is DI. See where the shit's coming from? It's not the gas tube, it's the same place as every other autoloading rifle ever made, including the pistol AR that you don't own.
>>29457093
sauce?
>>29462304
Wait, so is there no carbon in the gas that the DI pushes inside the bolt carrier to begin unlocking the bolt?
how much is a hk416 in the us anyways?
and are the sigs made by sig usa?
>>29462374
The gas inside the bolt carrier is contained within the bolt carrier, and vented out the ports on the side after a firing cycle as you can see in that gif.
It never gets inside the receiver; it's irrelevant how dirty the gas is. This is where the myth comes from, because people are so mindbogglingly stupid that they can't see >>29457144 lacks a bolt carrier, instead depicting the gas being poured straight into the receiver. It was probably made by a company promoting or producing piston ARs.
>>29462374
that gas is ejected out through the ejection port.
most of the shit comes in through the barrel in both systems.
theres more in the DI system, but not anything that really matters.
>>29462304
Images of guns ejecting rounds is so damn sexy.
>>29462400
I believe that image was crearted by Adam Arms.
But this brings up a bigger question. If a DI action is just as clean as a piston setup, why did H&K go to all the trouble to redesign the M27 with a piston?
The only rationale I have ever heard is that DIs heat up and foul up their lubrication more quickly. So if that's not the case, why did the engineers retool the whole thing.
(And please don't say the engineers did it for dishonest patents or some other completely unverifiable reason.)
>>29462436
can think of some reasons,
I guess us europeans like pistons more, so easier contracts in this market.
but probably the most important, in arctic conditions you dont want hot gasses everywhere that melts snow. you also want that extra force or hamfisting as another anon called it, to break possible freeze ups.
the m27 is used in automatic, so its good to get as much heat as possible away from the gun.
the cleanliness isnt really an issue at all, its just a meme thats used in marketing. guns are designed to run as dirty as they are. nothing wrong with a dirty gun
>>29462089
No you haven't. You claimed ARs have firing pin springs, then used the one special snowflake model that does and held it up as being common AMONG ALL ARs when it is a very small portion of the civilian market, and only a slightly larger portion of the military market. You never specified piston or DI.
>>29462249
>Smallest branch of the armed forces adopts it as a supplemental automatic rifle
Lemme know when they replace their M16s with it. As it stands, the DI Mil-Spec pattern AR is by far the most common rifle with pistons falling in the minority, and H&K 416s being an even smaller minority among them.
>>29462436
Because the M27 is an H&K416. The 416 was designed as an SBR to be used with a silencer for SF. This makes sense to use a piston. H&K simply added a longer, heavier barrel and submitted it for testing and it one. They didn't design it as an automatic rifle with a piston, they designed it as an SBR with a piston and then adapted it.
>>29462688
Why would the higher gas pressure of a short barrel with a suppressor favor a short stroke piston?
>>29462700
Because with a stoner DI system a suppressor overgasses the system and causes premature parts wear. A SS piston is a good idea with a silencer/SBR combo, but doesn't offer any improvements for a standard length barrel.
>>29457278
Carrier Tilt is a thing, but most big companies have devised their own way to deal with it. You might still have problems in the long run with piston conversions, but rifles like the HK MR556 and the LWRC M6 series will not be impacted by it. Someone put 67,000+ rounds through an HK416 upper and it was a nonissue. It would only occur on a poorly engineered or nigger-rigged piston system
>>29456959
Pro:
Short stroke piston reduces the heat in the receiver
Allows for more easy gas regulation.
Con:
Requires receiver rails to avoid bolt carrier tilt
Increases heat in the handguard
Prevents all recoil impulse from being imparted in line with the barrel
It's debateably more reliable than DI. It definitely runs cleaner.
Usually you can get a suppressor to run more easily with a well designed piston system.
>>29462627
gee I dont know
>>29461090
>common piston ARs
>>29461713
>common piston ARs
>>29462051
>common piston ARs
I know ar-10 uses springs, and quite a few piston ARs use firing pin springs.
when you dont have gas rings on the bolt, its too easy to move around so you need a spring to extend it. mil spec ar-15s dont use them, but I think some DI ARs use them too
>>29462688
wasnt the 416 just a "mid life redesign" or whatever they call it, like they did with the SA80?
HK wanted in on the m4 market, and they are known for reliable piston systems
For everyone all the clean memers here, cleanliness is indeed a big issue.
Firing 6-10 mags out of an M16 will cake so much carbon around the bolt carrier group that the bolt won't fully cycle every 5-10 shots requiring manual operation of the charging handle or forward assist.
Firing 10-15 mags through an M27 full auto, the bolt carrier group has about has much buildup as an M16 would after 1 or 2 mags. Also, you can fire an entire mag full auto and the bolt carrier is only warm to the touch.
Maintenance on the M27 is far easier because of this as well.
>>29463247
Wow, there is genuinely a person alive today that thinks this is true.
Have you been loading black powder into 5.56 cases by chance?
>>29456995
Moron detected.
>>29456995
I've owned both; and there are no distinct advantages to owning a piston AR. It's heavier is almost every single case, and I've owned one of the lightest on the market.
Any DI AR will almost in every case beat out a piston AR; Henderson Defense out in Nevada has run through ARs by "dumping mag after mag" and they have found even a PSA built AR will out last a LWRC which fails after 15,000 rounds; the return spring is warranted only to 16,000 or just shy of it.
Pistons cause more heat in the piston housing (where the gas block is located) but their barrels are typically cooler. They suppress differently, can be adjusted faster and have proprietary parts out the ass; from the BCG to the entire piston system. Carrier tilt is only an issue for lower end models or shitty versions which have made their way out the market; and if you can buy an anti-tilt buffer if it makes you worry.
They're not more reliable; they're heavier, they cost more and you must go through the factory for every replacement part concerning the piston system and BCG.
So, yeah, what's the difference?
>>29463930
Their, Henderson Defense's, statement on piston AR-15s. And granted, this is retardedly cruel testing but if piston systems are so much more durable then they should be atleast out pacing DI guns. The bullshit of "it shits where it eats" is just that; the small amount of fouling that accumulates is nothing to be concerned about, but I know some fag somewhere felt his charging handle get gritty and thinks he has to get a piston gun.
Get one if you like the technology but it's gimmicky; and I have never seen a difference in the two other than price and quality of other parts based the price tier.
Barrels? DI rifles win because that's where the money is spent on most mid to high end DI rifles; Piston rifles spend more of the proprietary system that factory uses.
>>29457144
>>29457142
From cleaning both, I will say that the DI system does NOT accumulate as much hard, thick, binding carbon as the piston.
The DI gets a thin coat of superficial, dusty carbon that hardly interferes with function polishes off quickly with a lightly oiled cloth. Cleaning m4s is a complete breeze. Pop a pin, pull some shit out, wipe wipe wipe, done. (Of course more in depth cleaning of the barrel, etc. takes additional steps, but that is regardless of piston/DI system)
I had to clean a few M240Bs last week, some of the Pistons were so fouled I had to use a rubber mallet to beat them out of the housing. Then I had to chip away the hard carbon with metal tools, and finish with an oiled rag. I've had to do similar cleaning with my beretta 391 when it has trouble cycling after only 150 rounds or so. The piston gets clogged with thick, hard carbon.
That being said, piston is useful for sbr. I will have to explore it myself to determine validity
>>29456959
You can move the mainspring forward around the piston and get rid of the buffer tube. That's really it and if your piston AR doesn't do that, the engineer completely missed the point.
>>294569590
Real deal baby
>>29462313
Strike Back. British opr8r tv show. breddy gud
>>29457013
>>29462304
>>29463917
Someone please explain to me why /k/ considers the whole "direct impingement = dirtier" thing to be considered disproved memery propagated by fudds.
https://www.youtube.com/watch?v=AzI33n6CdAI&t=39s
Look at 0:39, you can see the exposed gas tube when the gun cycles. Isn't that thing going to be spewing all sorts of foul shit inside the rifle's action during firing?
I'm not saying I haven't seen all sorts of reliable direct impingement AR-15s, but to accuse someone of "memery" for saying DI might be an inherently dirtier system than short or long stroke gas pistons is rather unfair.
I'm not trying to be an asshole, I'd be more than happy to change my mind if I got an explanation.
>>29462006
Thats what happens when you over lube
>>29464203
negligible difference despite a test using two different kinds of ammo
>>29464203
You can see my post here for a general overview
>>29463997
The DI fouling is largely thin, whispy carbon distributed fairly evenly on the bolt carrier and chamber, it becomes present after only a few rounds, but it is not hard, gunky fouling and it does not interfere with function (until you put an absurd amount of rounds through without cleaning). A wipe down will get it off
The fouling of the piston gun collects AT THE MECHANISM. The piston becomes clogged with hard, viscous carbon material that does, in fact, interfere with cycling. It must oftentimes be chipped or scraped away. The piston, when clean, does give a hard, sharp impulse to cycle the rounds, but when fouled it gets fucky in a hurry.
>>29464270
Interesting. Unfortunately I've never owned an AR, much less cleaned one. All the rifles I own are slavshit, including two AKs.
Would an AR run into problems with carbon buildup in the action if it was digesting allegedly dirtier, less than ideal ammo? Such as Tulammo or Wolf instead of Remington?
One of the oft repeated things I've heard about the reasons for the AK's design was because of Russian experiences with shitty ammo during WWII, rather than any belief that Russian conscripts were going to be uncharacteristically neglectful of the rifle.
>>29463883
This is coming from personal experience. My job is to carry an M16 (battalion just upgraded to M4's actually so no M16 any more thankfully) and I used to carry an M27.
M16's constantly get too dirty to cycle properly.
You can fall back on your countless hours behind a keyboard, but that's not going to change reality.
>>29464358
AR-15s are fucking amazing.
If you actually want a utilitarian rifle, so mass produced with a vibrant aftermarket that it's practically disposable... The best barrels and manufacturing in the USA...
Get you a high quality AR-15.
>>29464358
The only thing shitty ammo will do in terms of fouling is accelerate the process a little bit. So if you clean every 200 rounds, clean every 150 instead. If you clean every 500 rounds, clean every 300-400 instead.
Unless of course you are buying ammo so cheap that the casing itself if the problem. You should not buy ammo that bad and it is not often a problem
>>29463883
And as for the ammo, nope, standard green tip M855, and occasionally blanks depending on the type of training we're doing, which are way worse than M855 as far as carbon goes.
>>29464391
You used to carry an IAR?
I call bullshit.
>>29464398
Point of clarification on the last (probably unnecessary) part of my post:
Even wolf won't be giving you bad case problems. I usually see it in shitty home reloads
>>29464404
They're currently issued right now, it's the first gun I got in the fleet.
>>29464391
The main reason the m16 cycles improperly when dirty is the fact that fouling in, on, around, etc. the magazine and feed lips plays havoc on the gi mags. Getting something nicer for a couple bucks per mag actually solves the problem like gypsy magic. But that isn't going to happen anytime soon.
Gotta love no anti-tilt.
T. 8 years of service guy
>>29464431
Well we put the same mags through the IAR's and they eat em up no problem. The only malfunction I see more often in IAR's is brass over bolt when firing full auto.
Rah'
>>29464431
right, and it's surely not feed lip deformation because of the shitty aluminum?
>>29462717
But that's what an adjustable gas block is for.
>>29464497
I never said it wasn't. If you would learn to read, I stated we should use better mags.
>>29464478
The IAR is not a good concept in general
Just another instance of the Marines being special snowflakes.
>>29456959
It won't blow up in your face when you fire it and you just came out of the water. Where it was made for actually.
All the other crap is just so civilians will buy it.
>>29464431
>gypsy magic
I smell a pink pie
>>29464866
While I agree that a lot of the equipment we use is far from the best, and a lot of it is outdated (both have a lot to do with budget), the IAR is great. I'd rather see a team of 3 IAR's and an M4/203 for the team leader. Especially if the barrel was a little shorter.
What don't you like about it?
>>29464866
IAR is an example of western infantry doctrine continuing is gradual gravitation towards Soviet infantry doctrine.
so hk got the csass contract.
that means even more piston ARs in us military.
why do they keep choosing them over DI?
A bunch of ARfags trying to justify a shitty system that's designed to make rednecks feel like Rambo.
How many soldiers in Vietnam did DI kill due to fucking up? How many in Gulf I? Gulf II? Afghanistan?
The shit hits the fan and you have an M16 or an AK47 to choose from, what are you picking? All the experts say AK. Hell our own troops come back and buy them because they picked them up in the field, used them, and loved them.
http://www.defenseindustrydaily.com/the-usas-m4-carbine-controversy-03289/
http://atwar.blogs.nytimes.com/2009/11/02/how-reliable-is-the-m-16-rifle/?_r=0
http://www.nola.com/military/index.ssf/2009/10/m4_suspected_in_deaths_of_us_s.html
http://m.washingtontimes.com/news/2014/aug/19/armys-quits-tests-after-competing-rifle-outperform/?page=all
Why so many people stand behind this junk that is literally getting soldiers killed is beyond me.
>>29461085
>torquing it downward
A rigid body that experiences torque moves about its center of mass. A smack to the top of the bolt carrier tilts it upwards not downwards. And the same thing happens with DI, because the gas doesn't magically beam itself into the middle of the bolt carrier but gets there through an access tube which sits - you guessed it - at the top.
>>29465447
they are talking about the rear end of the carrier tilting down. but you are correct, tilting up would be the correct term.
the force of the flowing gas is not enough to exert any real force on the gas key. it comes from the expansion inside the carrier. which creates a force parallel with bore axis.
but tilt is not a problem in properly designed piston ARs
the 416 in OPs pic has longer bolt life than m16s. so the peening of lugs are BS.
IMO a properly designed piston AR are marginally better for military use than a properly designed DI AR.
for civillian useyoure just fucking yourself in the ass by buying an expensive gun with propriatary parts, which ruins the biggest appeal of the AR platform
With a suppressor and a piston ar, do you take really less gas in your face?
The adcor gas piston look nice.
On the topic of pistol ARs, there's a NIB POF P415 that comes with a Harris Bipod, 5 Lancer 20 and 30 round mags, but with no optic all for $1300.
I was thinking about buying it as my first AR. Thoughts?
>>29465505
It's not just when the pressure front arrives at the gas key but also when the system is under pressure, i.e. when the front has reached the last corner of the bolt carrier and there's equal, but still high pressure everywhere in the whole system. The force exerted by a fluid is proportional to the area it acts upon. This principle is e.g. being exploited in the hydraulic press. Larger area - larger force. And since the gas key has it's opening at the front there's more area for the gas to exert force upon towards the back. This means there's a net force acting in backwards direction above the center of mass of the bolt carrier which causes it to tilt upwards.
>>29465797
There's some mechE's white paper floating around showing that piston guns exert roughly 10x the axial tilt force as the DI's gas piston. I have noticed more wear (cosmetic only so far, but it's only 1000 rounds in) on the bottom of my buffer tube on my piston gun.
I made my peace with it before jumping in. I factored in the cost of a replacement tube as part of going the piston right.
>>29466564
what kind of gun do you have?
>>29466602
Adams Arms upper on a milspec lower.
>>29465345
>http://m.washingtontimes.com/news/2014/aug/19/armys-quits-tests-after-competing-rifle-outperform/?page=all
>A third graphic shows the M4A1 performed best for Class 3 stoppages, which are more significant failures that require a specialist, or armorer, to clear.
>It achieved 6,000 mean rounds between failure. Gun āCā achieved about 4,500 rounds.
>HK fags on suicide watch since 2014
>>29466564
>roughly 10x the axial tilt force
This should depend on the differences in gas pressure and the point at which the net force acts upon. The further away it is (vertically) from the center of mass of the bolt carrier, the greater the torque, ceteris paribus. But in general, yes, the piston should exert higher torques. How much depends on the individual construction.
I just wanted to make clear that both have torque. One cannot get away from it totally.
>>29464391
Yeah? I've seen piston systems clog up after 3000 rounds because it compacts the fouling on the face of the piston which makes it way into the system.
But yeah, stroke the cock of the piston.
>>29466925
>cheap guns are shitty, more news at 11
have you seen that happen with the m27?
shitty drop in kits are just that shitty.
first the m27, and now the M110 is getting replaced by a pimped hk417.
theres a possibility that france will adopt it for ther regular forces too.
>>29464164
Thank you, anon. Been hearing about that show, gonna check it out.
>>29464995
It simply does not replace the role of the m249. It is a great weapon, but it's purpose as a main for the automatic rifleman just robs the unit of a significant amount of firepower.
Many marines will cite that it is more accurate, but that's what you have your riflemen for!
>>29467133
why not keep the m249 and give m27s to the riflemen?
>>29467204
Great question.
I'm still waiting on an answer from the marine corps
>>29464395
What are those red buttons? Snap caps?
>>29457074
Hey moron, DE uses long-stroke.
>>29467374
mines, the red ones are remote mines. if they are green they are proximity
>>29456959
In an AR? Literally nothing unless you're a Knob Creek type guy that wants to run a full-auto suppressed rifle often.
>>29465345
>Hell our own troops come back and buy them because they picked them up in the field, used them, and loved them.
The bullshit detector just went off the scale.
>>29467420
What the FUCK did you just call me?
