Why Has No One Else Used the AR DI System?

One possible explanation comes to mind...

Once you copy the AR's DI gas system it makes sense to also copy the barrel, bolt, carrier and upper receiver which are married to the gas system. Then of course that is a drop-on to a cheap and efficient lower receiver...

Pretty soon you have an AR-15 clone or near clone so why bother reinventing the wheel. Especially when ARs can be sold cheaper than most other semiauto center fire rifles. No doubt the DI gas system could be used in a very different rifle but I sure wouldn't design one today and expect to compete with the AR.

No idea but the Swedish Ljungman (and derivative Egyptian Hakim) are DI and predate the AR.

Mosin Bubba said:

This is probably going to come across as bait, but this is just a question I've been thinking about.

Every aspect of the AR has been copied to death. Nowadays any vaguely military-ish gun you see is going to have the same mag release, same safety, probably a straight line stock, probably a break-open upper receiver, etc. You can even buy lever actions with the M4 collapsible stock. But as far as I know, the action of the AR is completely unique. The only other DI gun I can even name is the French MAS, and it's not the same as Stoner's system.

Now piston ARs vs DI can be fought until the mods want to lock the thread - and that's absolutely not the point here. The DI system has been proven to work, and it's very functional. I was just wondering how virtually all other elements of the AR have become the template for a combat rifle over the last half century, but every single one has avoided its gas system.

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Do you have any idea how many companies manufacture AR15 style rifles?

Warp said:

Do you have any idea how many companies manufacture AR15 style rifles?

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I don't. How many are there? I know there's less than there might at first seem to be because many of the companies buy parts from the same manufacturers.

Because it is rather limiting in its design.

Once you copy the piston design, you will find you will have to copy much of the rest of the internal parts, and all of the design compromises they bring with them.

Or, you just copy the whole thing and be done with it.

Mosin Bubba said:

This is probably going to come across as bait, but this is just a question I've been thinking about.

Every aspect of the AR has been copied to death. Nowadays any vaguely military-ish gun you see is going to have the same mag release, same safety, probably a straight line stock, probably a break-open upper receiver, etc. You can even buy lever actions with the M4 collapsible stock. But as far as I know, the action of the AR is completely unique. The only other DI gun I can even name is the French MAS, and it's not the same as Stoner's system.

Now piston ARs vs DI can be fought until the mods want to lock the thread - and that's absolutely not the point here. The DI system has been proven to work, and it's very functional. I was just wondering how virtually all other elements of the AR have become the template for a combat rifle over the last half century, but every single one has avoided its gas system.

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First, the Stoner AR system is NOT a DI system. DI systems do no use an expansion chamber. Instead, the gas "impinges" directly on the carrier, flowing directly from the gas tube.

The AR system uses an expansion chamber. The gas has to fill an expansion chamber that is a cylinder sealed by a piston. In this case, the bolt (tail portion) is the piston and the carrier is the cylinder. I guess you could call the AR a "cylinder driven system".

Second, If I were designing a new rifle, the only reason I would not choose the Stoner cylinder driven system (aside from possible patent infringements) is because the overall length of it, from muzzle to the aft end of the receiver extension. I suppose one could shorten the carrier and maybe figure out a way to move the action spring to on top of the carrier, but it seems it would take a bit of engineering gymnastics to make it happen.

Most piston driven systems that are copied have do not have their action springs located behind the carrier/bolt. The FAL is an excellent piston driven design, but it too is rarely copied. What does it have in common with the AR? It's action spring is in the buttstock. To make the folding stock Para version, they had to modify the carrier and dust cover to hold the action spring above the carrier. (FAL Paras are awesome rifles, by the way.)

In my opinion, the two reasons the AR Stoner system aren't becaue problems of functionality or reliability, it's due to over all length of the system and patent rights

the AR-15 isnt really a true DI system like the MAS 49/56, and my MAS is incredibly reliable, instead of blowing gasses into the bolt to expand the spaces within, the MAS simply has a 1/4" or so stub of the gas tube that sits inside a pocket in the front of the bolt carrier.. incredibly simple design with zero moving parts added vs most your piston systems

theres nothing wrong with DI itself, the MAS 49/56 is very reliable, and the HK which is delayed blowback will blow even more gas and fowling into the receiver than the AR ever will, the only problem i have with the AR gas system is that its more complex than it needs to be with no improvements or benefits over a true DI system to justify it

The Stoner system is more forgiving and uses its gasses to greater mechanical advantage than a true DI system

what about the AR has been "copied to death" exactly?

MistWolf said:

...(aside from possible patent infringements)...

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The patent protection on the Stoner gas system expired in the 1970s...There are no restrictions on that account*.

The whole point of doing the gas system the way it is done it to get the barrel axis, the piston axis and the main driving spring axis all coincident. This gets all the recoil thrust inline. To move the spring away from the bore axis negates this, therefore, there is little reason the keep the rest of the gas system in line.

__________________________
In fact, nothing on the AR-15 is still protected by patents, otherwise nobody could make a legal clone, Colt would have then shut down, or make them pay royalities. All Colt owns are the actual drawing package, and the name "AR-15". The drawings can be reverse engineered, and some were accidentally released, so they are no longer exactly secret.

a large margin of the civilian market has been convinced the DI system is the worst design on earth, and that Colt's QC during Vietnam was the fault of the DI. That will keep it out of the civilian market. The design is pretty straight forward, so any attempt to copy the gas setup will result in a nearly identical design, so may as well just copy it. The AR system is cheap, and has a long service life per unit, and thats what the government likes the most. Looks like the world is convinced that a 'self cleaning rifle' is only self cleaning if you never have to take out the trash. You don't leave the crap in the oven after you use the self clean feature right? The big advantage of the system is the accuracy, and most armies dont need that level.

mjsdwash said:

a large margin of the civilian market has been convinced the DI system is the worst design on earth, and that Colt's QC during Vietnam was the fault of the DI. That will keep it out of the civilian market.[1] The design is pretty straight forward, so any attempt to copy the gas setup will result in a nearly identical design, so may as well just copy it. The AR system is cheap[2], and has a long service life per unit, and thats what the government likes the most. Looks like the world is convinced that a 'self cleaning rifle' is only self cleaning if you never have to take out the trash. You don't leave the crap in the oven after you use the self clean feature right? The big advantage of the system is the accuracy, and most armies dont need that level.[3]

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[1] With around 4 million AR-15 and AR-15 style rifles in the US alone, it sure didn't do a good job for keeping it out of the civilian market...
[2] Actually, the cost of an M16, bought in Army volumes, is comparable to other military select-fire 5.56mm weapons, neither lower nor higher.
[3] But, 95 countries seem to find the M16 worth it.

lysanderxiii, i was praising the design, and critisizing the bashers.

lysanderxiii, i was praising the design, and criticizing the bashers. Its just a good enough design to not need replaced. i was saying the bashers will keep a SIMILAR, but not the same system off the market. People like the ar, because it mostly works. Why go with a new design similar, but not as good for wear, cost, and history? Also, look at the old contracts from the 90's, with FN, they were CHEAP! Plus they have an incomparable receiver life.

...because it's so superior, and not a weird dead-end of a technology which has always been the Achilles Heel of the AR platform



TCB

The Stoner system is more forgiving and uses its gasses to greater mechanical advantage than a true DI system

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This.

As far as the reason the system has not been grafted to other rifles, that's been pretty well explained. With the variety of configurations and cartridges available in/on the AR-15 and .30-8 AR platform, it would make little sense to develop a new rifle that uses it's gas system but is not compatible with the plethora of other parts and accessories. As you noted:

Nowadays any vaguely military-ish gun you see is going to have the same mag release, same safety, probably a straight line stock, probably a break-open upper receiver, etc.

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Which means if it's copied any further, any differences end up being purely cosmetic or academic, with the disadvantage of requiring proprietary parts and accessories. So it makes more sense to just carve out fancy billet receivers with cool logos and call it a day!

Mosin Bubba said:

This is probably going to come across as bait, but this is just a question I've been thinking about.

Every aspect of the AR has been copied to death. Nowadays any vaguely military-ish gun you see is going to have the same mag release, same safety, probably a straight line stock, probably a break-open upper receiver, etc. You can even buy lever actions with the M4 collapsible stock. But as far as I know, the action of the AR is completely unique. The only other DI gun I can even name is the French MAS, and it's not the same as Stoner's system.

Now piston ARs vs DI can be fought until the mods want to lock the thread - and that's absolutely not the point here. The DI system has been proven to work, and it's very functional. I was just wondering how virtually all other elements of the AR have become the template for a combat rifle over the last half century, but every single one has avoided its gas system.

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there is very little that is actually unique about the AR.. the in-line stock, bolt design, barrel extension, two-receiver idea, and many others were copied from other rifles, the AR-15 is just a pile of other peoples ideas slapped together by eugene stoner with a couple bad ideas of his own

The same could also be said about every other firearm designed since John Browning died.

There are only so many ways to skin a cat.

rc

there is very little that is actually unique about the AR.. the in-line stock, bolt design, barrel extension, two-receiver idea, and many others were copied from other rifles, the AR-15 is just a pile of other peoples ideas slapped together by eugene stoner with a couple bad ideas of his own

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Yeah, he definitely borrowed from all those other ultra-light designs using high strength aluminum and composites, as well as the first-of-it's-kind gas system, bolt design and integral lugs in the barrel extension

Every design for more than a century has borrowed features from others. That doesn't make them any less innovative. Small arms a a very mature technology, and were even in the 1950s. The sooner you stop hating the AR for fabricated reasons and admit Stoner was a design genius, the sooner we can get on with useful, intelligent dialogue.

MachIVshooter said:

Yeah, he definitely borrowed from all those other ultra-light designs using high strength aluminum and composites, as well as the first-of-it's-kind gas system, bolt design and integral lugs in the barrel extension

Every design for more than a century has borrowed features from others. That doesn't make them any less innovative. Small arms a a very mature technology, and were even in the 1950s. The sooner you stop hating the AR for fabricated reasons and admit Stoner was a design genius, the sooner we can get on with useful, intelligent dialogue.

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umm, the bolt, lug design, and barrel extension are all copied from the M1941 johnson rifle, its gas system is one of the least desirable features of the rifle so much so no one else wants to put it on their rifle (hence the topic of discussion) and with all that super duper fantastic futuristic space age machined aluminum it still weighs about the same as the AR18 or an AK74

dont confuse not blindly worshipping it for something its not with "hate"

It's not just that "nobody copies the AR" and comes up with a new rifle that is "DI." There are other designs just as unique and they are being ignored, too.

Like, the HK roller lock bolt. I don't see it being copied by anyone, either.

There is the ARES SCR, tho.

The barrel extension of the Stoner design has been, repeatedly. There is more to the design than the gas action. Bolt actions and lever actions include the barrel extension design, now, as it makes the receiver an unstressed part. The BLR uses an aluminum receiver because of it.

Most battle rifle designs since the introduction of the M16 frequently copy the control layout, and many also use the same identical magazines. The barrel extension is used on other guns, and most of the AK "upgrade" parts are AR high end designs modified to fit the Kalashnikov to update it. The buffer extension tube is frequently used on other guns to mount an AR stock and create a hybrid traditional gun with tacticool features. Plenty of shotguns and a notorious lever gun have been done that way.

The gas action is just one feature - plenty of the other stuff is being copied quite a bit. In comparison to the HK, it's prolific.

justin22885 said:

the AR-15 is just a pile of other peoples ideas slapped together by eugene stoner with a couple bad ideas of his own

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Amazing how such a bad idea could become the most popular rifle in America and be advocated by virtually every experienced, professional trainer out there. Stoner's got them all hoodwinked, eh?

umm, the bolt, lug design, and barrel extension are all copied from the M1941 johnson rifle

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The lug designs are similar. The bolt itself, not so much. Unless you're trying to take it as far as calling all rotating bolts copies, in which case you gotta go back to the 19th century for origins.

I'll give you the barrel extension, had forgotten that about the Johnson, although there are still noteworthy differences.

its gas system is one of the least desirable features of the rifle so much so no one else wants to put it on their rifle (hence the topic of discussion)

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Says you and a bunch of AK nuts. The system works, and works well, whilst saving roughly 1/2 pound.

The reasons it is not copied have been pretty well laid out above, and have nothing to do with perceived shortcomings.

and with all that super duper fantastic futuristic space age machined aluminum it still weighs about the same as the AR18 or an AK74

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Methinks you forget how light the original guns were; just 5-1/2 lbs with 20" barrels. Don't use the modern HBAR versions laden with accessories as a metric. You could, however, consider how far it's gone with modern carbines, title I guns weighing in at well under 5 lbs, some close to 3. I built a 4.6 lb title I AR for under $500. Find me a non-NFA Kalashnikopy that light. Heck, find me an AK SBR that's in the 4 lb range. Good luck.

dont confuse not blindly worshipping it for something its not with "hate"

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Do not create false dichotomies of adulation and loathing.

To build on that, Stoner's design also rules the roost in pretty much every form of competition where it's allowed to play, including both action and precision shooting sports.

Desert Eagle copied the AR Bolt design and barrel chamber for their pistols.

The AR design has been copied in different ways, but like everyone else has said the parts of an AR work so well together and has had so much engineering and thought put into them, that when a person wants to use a part it just makes sense to use the other parts that are built to work with said part. Doesn't mean that someone won't do just what you are talking about but the end result firearm would have to be revolutionary for it to be worth not using the other parts built for it.

Eugene Stoner did develop a ingenious firearm, there are so many haters out there, or at least so many that want to put down the AR, but the fact of the matter is, is that the design is a great one. And that doesn't downplay the ingeniousness of H&K, Kalashnikov, Sergei Mosin, John Browning, etc. But this last paragraph wasn't what the original topic was about so I'll leave it at that. MachIVShooter, said it best above.