Smyth Busters: The AR-15, Direct Impingement or Piston Operated?
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- čas přidán 5. 09. 2024
- Today, Brownells Gun Techs™ Steve Ostrem and @CalebSavant want to settle a debate. Or maybe just stir the pot. The debate among AR-15 fans is that the AR-15 platform actually DOES NOT have a direct impingement operating system. Steve asks the pertinent question: So where's the piston then? Caleb gets technical and starts by defining terms.
A traditional GAS PISTON operating system - like on the AK series, FN FAL, HK416, or BRN-4 - sends combustion gas through a gas port in the barrel into a sleeve that applies pressure on a piston that pushes on the carrier to unlock the bolt. In a DIRECT IMPINGEMENT operating system, instead of the gas pushing on a piston, it goes down a gas tube and pushes directly on the carrier to cycle it.
The AR-15 works a little differently. The gas goes THROUGH the carrier and pushes directly on the BOLT to move it. The carrier has two holes that vent the gas out of the carrier and out the ejection port. This helps minimize muzzle rise, which can be quite pronounced on a pure direct impingement system. But the big news is that the bolt acts like a piston and the carrier acts like the sleeve. So the AR-15's operating system really IS a lot like a traditional piston system!
Pure direct impingement rifles like the old Swedish AG42 or French MAS-49 get a lot of carbon fouling on the carrier because the gas doesn't get vented out like it does on the AR-15. The AR-15's bolt and carrier still get dirtier than those of a traditional piston-operated rifle, which keeps all the gas (and all the fouling) up front in the gas block.
So the "myth" is not busted. The AR-15 actually is not a true direct impingement rifle because the bolt itself acts as the piston and the carrier acts as the sleeve.
Merry Christmas everyone! I gotta give a shoutout to Rad Labs 3d for the sweet custom Brownells AR stand. Oh, and if you haven't yet, go watch Violent Night the movie.
When are we getting the sexy christmas calender
I want a cut in half AR
I’ll second the calendar request. I wanna see kaleb all cute as Mr February
Internal piston doesn't sound catchy. We have short stroke and long stroke, why not call is the Stoner Stroke Piston (LP, SP, SSP for dem acronyms)?
@@PAIsIllegal probably not one worth owning honestly. A barrel is not something you want to cheap out on. There are affordable barrels that are good but I would stay away from hunting "dirt cheap" when it comes to key components in general.
Stoner was a freaking genius. The AR is basically a tube gun, no reciprocal mass that is of the bore axis except for the tiny hollow gas key.
What do you mean? The bolt is reciprocating.
@@freeandcriticalthinker4431 I think he meant to say that all the reciprocal mass is inline with the bore. Other than the gas key.
*OFF the bore axis
@@freeandcriticalthinker4431 I think he meant to type, "no reciprocal mass that is ABOVE the bore axis except for the tiny hollow gas key."
Being "above the bore axis" is the KEY thing. Hah, pun!
67
Kalashnikov was more genius.
I like how Steve tries to play the dummy role, while we all know he's very intelligent.
if anything he has probably known this all of his working life.
I like how he just gives that ho-hum look and takes another drink of coffee ☕️.
I think the gray haired guy hits that coffee cup a little too much. This video should be used for a drinking game.
@silent1967 After they stop the video shoot, that coffee swilling guy has to take a serious piss
@@jetboy770371 Don't worry, when you get as old as he is you'll be pissing a lot too, whether you drink coffee or not.
A couple years ago, I heard Chris from Small Arms Solutions refer to it as an "internal piston" system. At first, it went against everything I had been taught about the system since I was issued my first M16A1 in the early 80's. Then he explained it much the way Caleb did, then the light bulb clicked on. I've referred to it as internal piston operated ever since. If I'm not mistaken, I believe there is old interview with Mr. Stoner where he calls it internal piston also. But I'm not 100% sure on that. Great video guys, as always!
Pistons are contained by cylinders. They are always internal. You had it right the first time. The entire bolt-is-a-piston story came from the patent attorneys and their creative writing - not Stoner. Ever heard of the cylinder being driven and the piston being dragged along? No. No you have not, except for the AR fiction
@@Ni999 Have you ever driven a SuperMoto?
@@woodrowcall3158 No and not all supermotos use rotary engines. See my other reply. The AR bolt is still not a piston.
So, it's an internal piston system???
@@Ni999 So it is a cup piston, much like the LWRCI piston only the carrier is the cup piston..
"AR-15, Direct Impingement or Piston Operated?"
AR-15: "Yes"
You guys explain everything so well that even a novice can understand completely.
That is the real genius of these videos.
According to Eugene Stoner: the bolt is the piston.
I sometimes refer to rifles like the AR-15 and the Daewoo K1 as being "internal piston" rifles, as opposed to "external piston" systems like the AK-47 or the HK-416.
Great vid. Would love a part two about cost differences, reliability of gas piston and more parts to break, weight and recoil differences as well.
See the Adams Arms video. DI vs there piston upper. The DI upper is dirty as hell and runs hotter!
It’s a piston gun disguised as a direct impingement gun, lol
When Caleb's pomade was made, Eugene Stoner was still sketching the AR design...🙃
That's some great AR education, many thanks
"Oh hey Steve, didn't see ya there." It's the little goofy things I love about these videos.
I would agree that the AR is technically a piston system.
Definitely a very elegant solution, seems like there's always something new to learn about the AR platform
As a motorcycle technician, I think I know a piston when I see one. 😂
"This invention is a true expanding gas system instead of the conventional impinging gas system." - direct gas, expansion, bleed off system
It is a piston, as described in Stoner's patent..
@@hairydogstail I didn't say it wasn't. Just pointed out that it isn't an impingement system.
``Your bolt acts as the piston...''. That is THE difference between the AR-15 platform and a piston driven platform like an AK.
"I'm not here to end it" and "that's a lot of syllables" totally got me. Lol. Good stuff.
Not only is it a piston gun, it's a long stroke piston since the piston travels the entire distance with the carrier
Why would you say that?! 😂
@@dieudonnesaive6603 Re-read what he wrote..
@@dieudonnesaive6603 Because it kind of is technically true, it's just missing the operating rod lol
@@Alex-12381 technically since the bolt isn’t fixed to the bolt carrier, I’m not sure it’s exactly true? The piston (bolt) is its own moving part aside from the carrier. It really just depends on what definition of “long stroke” we roll with. There’s a hundred different ones out there, all of them kinda flawed in one way or another.
Who knew that Steve is a fan of Pitch Meetings? Super Easy, barely an inconvenience!
I love these guys. The dynamic duo of Guntube.
Great deep dive into the DI gas system. One could argue, a lot of the heat is dissipated over the entirety of the DI gas system, vs all heat collected at the gas piston, forward barrel? Both systems have their pluses and minuses.
Okay, there are legit advantages for the Stoner system, but this is some extreme copium.
Keeping all the gas and fouling concentrated in one area makes cleaning much easier.
@@WaterZer0 Maybe, but all the heat, and weight, IS concentrated near the muzzle. That's not to MY liking. Your mileage may vary!
@@03redrubi I understand the weight issue, but where else would you want the heat?
@@WaterZer0 Not where my accessories, and hand are.
DI has some advantages like self-cleaning of debris too.
THANK YOU!! I have been hearing people argue this point back and forth for YEARS, but none of them have been able to actually explain what direct impingement OR piston driven even MEANS. And since I didn't know myself, all I could do was smile and nod. Glad someone finally came along to explain it and put this shit to bed.
And this is where you get adjustable gas bolt carriers as well. Though, there aren't many of them.
Just when I was finally understanding the difference between a direct blowback v. gas-recoil operated pistol (And at an elementary level at that) Steve and Caleb drop this one on all viewers! Good, interesting video (as always from the Smyth Busters duo), but I’m sure I’m not the only viewer still not certain I could explain the differences between the two operating systems, even after viewing.
It literally just comes down to where the gas is being introduced into the mechanism. At the chamber, at the gas key, at the piston face, at the bolt face, etc. The gas tube on an AR-15 is just a tube that dumps the gas into the receiver, that's it.
@@tedhodge4830 : TY Mr. Hodge. Happy Holidays.
As I already knew. Once you understand what direct impingement really means, and see how th AR works, it's self evident.
I want to be able to like the Steve and Caleb videos more than once.
Great videos. Not only informative, but entertaining.
Videos like this bring out the comments that prove society does not care to know proper language and the definition of words.
Eugene Stoner was an Aerospace Engineer by trade. You can't have unbalanced forces on aircraft and expect them to fly well. He felt the same way about firearms. He wanted all action/reaction forces to be on the bore axis. I've seen slow motion video's of AK's being shot and you can see the barrel flex down slightly as the piston is pushed out of the cylinder about an inch above the bore axis.
Stoner was never an engineer..He never went to college..
Ak vs Ar = apple's vs orange's
It's an old and boring conversation
How did you guys know I was arguing with my brother about this on christmas?!
I'm late but wanted to drop by and say merry christmas and happy new year to Steve, Caleb and the Brownells crew!
PS. My dad already had Die Hard on when I arrived for our Christmas dinner..
from NH, Live free or Die!
Live free or die needs updating, I want to live free and live.
I propose the following change.
Live free or die fighting.
&
Give me liberty or give me death needs updating as well.
I have Liberty, death can wait.
@@ellerybice3787 The sentiment is there, it reads a little harsh out of context but I like the truth behind it.
I wish NH would bring in the Gadsden license plates like Virginia, the old man on the mountain is, well, old. Lol
Nice theory....
But mechanically speaking,
it's just an expansion chamber, instead of a pistons.
no because it reciprocates according to the gas pressure which is a piston
@@AR15andGOD nope, it's as an expansion chamber, not a piston, just to unlock the bolt. An "apparent piston".
Those two holes are perfect for dropping oil in to get your gun back up and running.
They are also perfect for blowing out ingress that shuts down external piston rifles..
Fueling an online gun argument? Classic Caleb moment.
Great video BTW
Three fun facts for everyone:
1) Everyone wants to be right all of the time.
2) Many people are stupid, but none of them realize it.
3) A P320 will not fire without the trigger moving rearward.
So one must define the term piston. If one agrees that a piston is a disc travelling in a sealed sleeve from a high pressure area often created by hot gases to the low pressure area within the contained sleeve. That movement caused by the pressure gradient often drives an operating rod that creates the desired effect.There is no piston in the AR15. The hot gas fills an expansion chamber within the bolt carrier forcing the bolt carrier rearward.there is some slight movement between the bolt and carrier as it unlocks but that in no way is the classical sealed disc travelling across a pressure gradient driving an op rod. There is no piston like structure in the AR 15’s operating system. The fact that the gas exerts it pressure within the bolt carrier makes no difference. The high pressure gas directly forces the bolt carrier to the rear. The bolt is just dragged along as the camming action unlocks it so it too is forced to the rear.
The bolt tail with gas rings is the piston. Desert Eagle and Mini-14 both have static pistons.
AR-10/15 piston just happens to be an integral component to the bolt, so after the tail is finished its duties as a piston, it cams and retracts along with the carrier once telescoped.
Loved this episode. This is actually a topic of many a heated debate as I've tried to explain that the AR platform is both 'a little bit' piston, and 'a little bit' direct impingement.
It is nothing direct impingement
Internal piston via gas impingement?
@@michaelhill6451 Except, the means in which the AR15 cycles is the very definition of DI. The only piston action is merely to unlock the bolt by pushing it forward. Some of the gas is vented off, but much of it is used to push the bcg rearward. This is why you get gas blown out of the gaps in the rear of the receiver near the charging handle. Using an earlier prototype that never made it into production and doesn't represent the final design as an example doesn't work, my friend.
@@michaelhill6451 And the debate continues. I guess I'll have to do some reading!
@@waruikoneko1635 you are not understanding the physics and saying Eugene didn't know better than you on his own design????? You got a wall of participation trophies, don't you.
I would not argue too much about the fact that there is a piston in direct impingement mechanisms because there is actally always some kind of piston-cylinder couple in any self loading firearm. Even in blowback ones where the cartridge case acts as a piston and the chamber as the cylinder and in recoil operated ones where the locked breech acts as the cylinder and the projectile as the piston). The special thing about direct impingement is that the energy conversion of pressurized gas into a moving mass needed for cycling is happening directly inside the bolt carrier and not inside the gas block or the bore. The right way to separate the direct impingement action of for example a MAS-49 and Stoner's design is to add the words short stroke or long stroke as prefixes. Per definition of ordinary gas operated firearms: A long stroke design let's the piston travel the whole distance of the bolt carrier. This is the case for the MAS-49. The gas tube just acts as a stationary piston and the bolt carrier as a mobile cylinder. The AR-10s and -15s are short stroke direct impingement actions because the piston a.k.a. bolt head moves only the distance needed for unlocking inside its cylinder (the bolt carrier). The Bolt then continues it's travel without separating the piston-cylinder couple any further which is 100 % how a short stroke gas operated action works.
Great video. I think that we can lose our minds delving into the absolute best term for everything. Back when I was in Army as an 18B we were taught that there were 2 types of gas piston systems (gas piston & gas tappet) now it’s normally referred to as long stroke gas piston and short stroke gas piston, which in my opinion makes less sense but it is what it is. As long as someone that should be in the know doesn’t call a “magazine” a “clip” or a “cartridge” a “bullet” I’m good, and there are plenty of high profile gun YT channels that use the term bullet when referring to a cartridge.
It’s actually a internal piston driven system that we somehow started calling direct impingement
You could argue that in the MAS and the AG-42, the bolt carrier is the piston, though rapped around the gas tube, rather than being inside the sleeve of the gasblock. So a "long stroke bolt carrier integrated spigot gas piston", while the AR-15 is a "short stroke bolt integrated gas piston".
Merry Christmas to my favorite firearms duo🎄🌟
Steve forgot to put his hip waders on for the level of BS Caleb was ready to sling on this topic… 😂
One important point: Eugene Stoner’s genius in designing that gas chamber inside the bolt carrier does something VERY important. The bolt is pushed *forward* while the bolt carrier is pushed backward. This relieves pressure on the bolt lugs, making it easier to disengage from the matching barrel extension lugs and reducing wear and tear.
It gives the gas a chamber to expand into that allows it to impart force to the carrier, allowing it to move. The delay caused by the carrier moving and the bolt staying locked allows the chamber pressure to drop sufficiently, relieving pressure on the locking lugs. The lugs want pressure pushing them into the lugs on the extension, that's why they're called locking lugs.
@@ShortArmOfGod I do not understand what point you are trying to make.
As long as it works when you need it to, call it what you want. Happy holidays gentlemen.
Great teaching. Thank you.
Direct impingement is this damn shoulder problem my surgeon hasn’t been able to fix since 2019😡
Works like a steam engine in a locomotive or paddle boat invented in the early 1800s.
A roller locker is dirtier than a MAS 49 or 49/56.
Shout out to Caleb’s barber for keeping that man looking fresh AF
ARRRGGGGG - and I had to get on Brownell's BRN-4 wait list
I've always tried to explain the AR never was DI even though Eugene Stoner called it that because the bolt is the piston and the carrier is the cylinder. I think Stoner simply said that out of simplicity to avoid having to explain the whole thing. Example of a real DI is the Swedish AG45B and the MAS 49 if memory serves me right
I've also tried to explain to people it's a bad idea to move the piston over the barrel on the AR because the AR was designed to have all the forces concentric to the bore axis. When the piston over the barrel producing accentric forces; now you're forcing the rear of the carrier down and dig into the soft aluminum.
Plus now there's nothing to counter bolt thrust pressure before camming open, the carrier key is now digging into the soft aluminum side. Plus the camming action to unlock the bolt without counteracting the bolt thrust pressure on the locking lugs will eventually break bolts as well.
The whole thing turned into a gun hipster fad when HK did that to solve the problem of being able to fire the rifle immediately after being submerged on water for the SEAL teams, not because it's a better configuration for those not firing their weapons immediately after being submerged without letting it drain first. They were willing to sacrifice the service life to be able to do that with the AR, are you?
In your reality, the cylinder is driven and the piston follows. That's a very strange concept for how pistons work to say the least. Stoner called it DI because that's exactly what it is. The company's patent attorneys are responsible for the creative explanation you've been holding on to, including the expansion chamber that is nothing of the sort.
@@Ni999 in rotary engines ( think sopwith camel or other WW1 fighters) the piston is stationary while the cylinder moves… it is a valid mechanical design
@@JM-jv7ps Good catch but no soap. I'll stand corrected for the non-linear example that only existed until the oil pump was made airborne and radial engines replaced rotary cylinders. Still a good catch though. Read the AR patent. Edit/PS - hung a well deserved like on your post.
@@Ni999 In both thermodynamics and mechanics it is a question of frame of reference. There really is no difference between sleeve and piston. The are being acted on by the same forces.
@@andresmartinezramos7513 That's true. It's also true that the AR bolt is not a piston.
I've heard this described several times before and this is a good description with visual aids. Thanks guys much appreciated.
I can almost hear the ARFCOM users angrily typing right now…
I would call it direct impingement because the gas is still interfacing with the bolt carrier in the action of the firearm, where with what is conventionally referred to as a short or long stroke piston the exchange happens outside of the action of the firearm. But I can see both sides.
IDI...
Improved Direct Impingement
The gas is still directly impinging (impinging: the act or fact of striking or touching something, or the effect produced by this) upon the bolt carrier group. It is just doing so in a way that is greatly improved over the methods of direct impingement utilized by previous designs.
It's pretty cool to see and hear it clearly explained 👍
With that better understood by me, I now get to wondering if Ruger's Mini-14 is actually best described as a direct impingement system gun? 🤔
Now I'm wondering if I have a homemade icecream churn or a homemade icecream bucket !
Hard to argue with facts. Great video guys.
Nomenclature has accepted the terms for simplicity of differentiating the types of piston or "gas guns".
Internal piston system to be specific
Steve - you miss spoke just a little bit at around 4.58 in the video. As I understand it, the bolt is locked in against the chamber because of the lugs. So therefore the bolt doesn't go forward - the carrier gets pushed rearward from the gas.
For people who understand the gas system, we know what you meant. For people who are trying to understand the gas system, what you said might be confusing.
I enjoy you guys videos, so keep up putting them out. I've learned a lot from you guys and others like you.
John
The forces from the gas still expand in all directions including towards the bolt when it is in battery. The force from the gas expansion has to be overcome before the bolt can move rearwords, I think that's what they meant.
Can you do a segment on Canada's deadliest and most prolific .22 gauge fully semiautomatic assault rifle, the Buttmaster?
Come on, we all know the dohicky moves forwards and back inside the thingamajig when the trigger is pulled. These guys are just making stuff up.
Who am I to disagree? I work at a Gun Range and am always learning from our Gunsmith, so I am not going to argue any points concerning operating systems, etc., but will be watching and learning what I can from you guys (Steve and Caleb). Thanks again for another great video.
Well here's the problem heckler & Koch are charging the United States Marine corps $1700 for each M27 IAR which is a 416 based rifle
The Army is acquiring M14A1s for $700 to $800 a piece
It seems to me that it's a lot better to tell a soldier who is already disciplined to run a cleaning rod down through an M4 as opposed to handing out $1700 just to have that Short stroke piston
It requires a little bit extra maintenance but the AR-15 direct gas impingement or internal piston depending on how you want to split things works perfectly for the United States military we've never had any major problems with it nobody has gotten killed because the gas system itself let's keep what works and not hand out almost $2,000 for a 416.
"This invention is a true expanding gas system instead of the conventional impinging gas system.” Eugene Stoner Patent
“It is a principal object of this invention to utilize the basic parts of an automatic rifle mechanism such as the bolt and bolt carrier to perform a double function. This double function consists of the bolts primary function to lock the breach against the pressure of firing, and secondarily, to act as a stationary piston to actuate the automatic rifle mechanism. The primary function of the bolt carrier is to lock and unlock the bolt by rotating it and to carry it back and forth in the receiver. The secondary function of the bolt carrier is to act as a movable cylinder to actuate the automatic rifle mechanism. *By having the bolt carrier act as a movable cylinder and the bolt act as a stationary piston, the need for a conventional gas cylinder, piston and actuating rod assembly is eliminated.*” Eugene Stoner patent
Maybe a direct impiston system? I just made that up, lol
Seriously though, you are correct and gave the best explanation to date.
Unless your running a non-transferable FA AR, have Joe’s $1.7T budget for ammo, and shoot everyday, a “direct impingement” system will serve you very well. The piston gun is cool and all, but as we add accessories to the platform, you’re better off loosing weight where you can, and carry more ammo - never run black on ammo! Also, as you age not so well like this ole retired combat gruntpa (ABN), you tend to gravitate to lighter systems, lol.
The first time I disassembled a "DI" BCG and saw the gas rings it always was a piston in my mind. The terminology merely identified where the piston doing the work was located.
The long stroke piston system is closer to direct impingement than the AR15 technically speaking.
I have heard them called "internal piston" operated.
Why is this debated. Its literally called a piston system in the bloody patents.
Bottom line they are all piston driven with different locations for the piston.
After shooting ARs and AKs and keeping a strict cleaning routine, I've found the idea that ARs are filthy to be blown way out of proportion. The AK piston head and gas tube get super foul. While it doesn't impact the receiver, detailing the gun takes just as much time as an AR.
The AR fouling issue in Vietnam was mostly due to using poor quality, but cheaper surplus ball powder that left a lot of residue and the rifle wasn't designed for. When used with the original IMR stick powder it was designed around, there was a lot less fouling.
But WAIT!!! There's more!!! One thing almost no one mentions... observe that the piston on the bolt, the section where the gas rings are, is approximately the same diameter as the cartridge head. While the gas is pushing back on the carrier, it is also pushing forward on the bolt, thereby equalizing the rearward pressure of the cartridge pushing back against it. This greatly reduces the pressure on the bolt lugs. This pressure equalization does not happen with piston systems such as the HK416 or the old Rhino gas piston from years ago. With a piston system the bolt lugs are subject to much greater wear and tear, chipping and breaking, as the bolt is unlocking under pressure.
If the residual bore pressure equalizes to the internal expansion system pressure, it should float, but the dynamic range varies with port location, size, ball vs stick powders, ambient temperature, etc.
Cyclic rate has more of an effect on bolt lug torsional load with residual bore pressure. Faster cyclic rate is harder on the bolt lugs, which is why CLGS suppressed exhibits earlier bolt fatigue.
@@LRRPFco52 Yes, not perfect equalization of pressures, but better than none at all, which is what the piston systems give you.
Thank you very much for this and all the other explanations. The info you guys provide really helps me understand the workings of my firearms. And the differences between many that seem very similar.
Good explanation. It would have been even clearer if you had a true direct impingement gun to show side-by-side (like you mentioned - the MAS 49/56 or the AG42/Hakeem/Rashid)
I believe that Stoner's patent filing calls it a piston system.
You might wish to point out that it is a "reverse" piston design, since the "sleeve" moves, while the "piston" is stationary. At first, until the carrier has gone far enough to rotate the bolt and begin extractione.
The Mini-14 is more direct impingement than an AR-15. Stoner called his system a piston in his patent. A piston needs an expansion chamber which the AR-15 has..I would call the AR a piston but the carrier is the cup piston like the LWRCI, only internal..
Yup. Mini-14 & Desert Eagle are direct impingement systems, as is the AG42.
I say it's a hybrid system, the gas acting on the gas key on the carrier as a DI to exert force to push the bolt back. and the internal piston system pushes the bolt and carrier apart ro unlock the bolt
I've always thought of the AR as a piston system. Gas rings on the bolt/piston.
Love you two! Wish there was a gun shop sitcom.
What I’ve been wondering is if in some similar manor with different methodology, how different is this Direct Impingement design from a direct blowback system on a smaller firearm.
I haven’t really studied Direct blowback all that much but from what I understand it seems as if bolt mass and recoil spring tension keep the bolt closed tight enough allowing for the force of the bullet being expelled to cause the next round of a direct blowback firearm to cycle as the bolt travels back and the spent casing is ejected from the firearm. In some ways, I’m seeing a lot of similarities with the Direct Impingement system and how the system uses the gas of the round itself to cycle the next round. Idk if there are any similarities at all but I thought it was a surprising analysis.
Great Video! I have both (DI"ish" and Piston).. I love both for different reasons. Piston definitely handles suppressors much better, and can operate even if fully submerged in water. My DI rifles are great as well, lighter recoil, flip is manageable with a muzzle brake. Both are great designs.
Stoner NEVER called it direct impingement. Some yahoo gave it that name. I've always called it a reverse piston.
Great information ,good comedy ( thx 4 all of the videos ) !
I have found inside of the bolt carrier gets a crusty power build up on the bolt behind gas rings on my di gun.with my piston guns none of course.
Yep, that's one of the biggest reasons to go short/long piston. The people that say it's a lubricant are in denial.
When I read critiques of the AR-15 there's a lot about them that makes sense.
I'm a fan of the rifle and all, but I've never had to fight a war with it in the mud and sand etc.
One point that stands out sharply to me: Gun designers take other guns and use the aspects that they like when designing new weapons.
The AR's direct-impingement system has not been duplicated by modern firearms. Why?
Is it because the benefits of the system are outweighed by the negatives? Maybe so.
Then again, the world's empire has been successfully fielding this gun for over 50 years now so what do I know.
Just my concerns.
The gas has to push something, that thing acts as a piston, so basically every gas system is a piston system.
The "round" (a rifle cartridge) does NOT travel down the barrel. Only the BULLET does. The rest of the round (the cartridge case & spent primer) is ejected from the side of the rifle.
lol
Serbu BFG50A is also DI.
So the bolt is the piston and the carrier is the cylinder, got it.
Interesting view! But the technical operation never lies…
Great video! Also, love the Ryan George mug Steve's got there.
Can the AR-10/AR-15 operating mechanism be described as using a piston? Yes, but it's also directly acting upon carrier itself by using gas pressure inside the carrier itself. The term "DI vs piston" colloquially just refers to an op rod striking the bolt face, versus gas going directly into the carrier, and that's really what people mean when they say a "piston gun" vs a traditional AR-15. It basically boils down to a semantics argument, which is losing the forest from the trees. The significance is that the "DI" system has hot, filthy propellant residue going directly inside of a high friction area, whereas the traditional short stroke system has that gas contained parallel to the barrel, which also has its own drawbacks.
The AR-15 design has a lot of drawbacks to it for each advantage, and that was seen when the US military was forced by the DoD to adopt the AR-15 as the M16 in Vietnam. Crucially, it didn't work very well with standard ball powder propellant, which the Army had a lot stockpiled since WW1, and they didn't have enough of the new recommended stick propellant. It was virtually unusable with conventional ball powder, and its performance in pre-adoption tests wasn't replicated in the field until the supply chain caught up with the demand. I think that's why no design like it existed before, and no design like it followed it even after the patents expired. Why on earth the Army weapons trials in the 60's didn't test the AR-15 for compatibility with the ball powder I don't understand. It would have saved a lot of heartache.
It seems like semantics though bolt has rings ( like a piston) but it seems like 2 actions or that the bolt is locking and unlocking while the bolt carrier blows back
I like the BRM design better but it seems that the push rod could give out from heavy use and would need replacement
Well, I disagree, AR-15 is what I called a gas impingement or indirect system similar from the MAS 44 / 49, AG-42, which is not piston operated, it does use a gas tube system which is inline with a gas tube. In the Stoner design / patent, the gas goes about 45 degrees down to a center bore cylinder chamber in the bolt / breech. There is a side vent meter that releases the gas in the center cylinder chamber. The center bolt / breech prevents the tilting of the bolt / breech and releases the gas. That's one of the reasons for the design. In the Stoner design / patent you still have the same problem of a lot of carbon build up in any gas / indirect / direct impingement system such as the AR-10, AR-15, M-16, M-4.
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The M-1 Garand, M-14, AK-47, has a long operating rod with a piston, this a minor problem in that it has to be stiff enough not to flex. This is the reason for the use of a direct /indirect impingement as there is no long operating rod at all in the MAS 44 / 49, AG-42, AR-15, M-16, M-4. The M-1 Carbine, which does have a short stroke system with a recoil spring and a short operating rod.
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One last thing, in the new Sig Sauer M5 / M7 military rifle, uses a "short stroke design" similar to the M-1 Carbine other than it uses the operating rod on top of the barrel with a long recoil spring.
The carbon has never been a problem with the internal piston..Test have proven this over and over..More fudd lore..The bolt does not tilt but rotates after the bullet has left the barrel..It is the residual pressure that cycles the action..
As long as it works, that’s all I care about
I consider it a piston driven system but i usually refer to it as DI to avoid confusion.
Or you could add to it and call it Indirect Inpingement 😅