What was wrong with Stoner's design?

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Precision

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Correct me if I'm wrong, but I thought Stoner designed the 5.56x45 cartridge to be fired from a 20" barrel. Correct me if I'm wrong, but I thought Stoner designed the direct gas impingement of the AR-15 to be utilized with a 20" barrel.

So why is it that all the AR-15s I see have 14.5" or shorter barrels? From what I've heard, it reduces the fragmentation/lethality characteristics of the 5.56, while also weakening the reliability of the gas system. I've also heard that Marines who are still issued an M16 variant (20") have less lethality and reliability issues when compared to soldiers issued the M4 Carbine (14.5"). The AR-15 simply wasn't conceived to be a carbine, much less an SBR.

Utilizing a short-stroke gas piston system (op-rod) can potentially solve the potential reliability risks, but not the fragmentation problems. So why does practically every civilian I've chatted with on here on insist on utilizing a DI AR-15 with a 14.5" barrel, all the way down to 10.5"?

DOESN'T IT CRIPPLE PERFORMANCE?
 
I think the shortcomings of 5.56mm and the AR platform are grossly overstated.

Our boys have been successfully killing lots of enemies with the M16 for half a century (much of that time with the shorter M4).

Too many folk seem to think the M16 should have the same single shot lethality and range as the bolt gun they take deer and elk with back home.

I also don't buy the idea that a piston system is any more reliable than the direct impingement system, in fact I would expect it would be prone to more issues as its a more complicated system. The KISS principal works.

I would trust my 16" directly impinged AR as much as most AKs.
 
The 5.56 causes massive wounds with the right loads for the job even out of a shorter barrel. Plus the fact that you can carry twice as much ammo for the same weight makes it a win.

Personally I find it a superior weapon compared to others. It's handling and ergonomics are superb, and as long as you run it wet, you will have little to no trouble.
 
Nothing is wrong with Stoner's design. The orginal AR was tuned to use a particular 5.56 load in a 20 inch barrel. Like many designs it works best with that orginal combo but doesn't mean it won't work with others, and then again not at all with others.

There's nothing wrong with a 10.5", 11", 14.5", 16" barrel and it will run same as the 20" models. It just so happens the orginal ammo is alittle too hot for 14.5" and 16" models to not require some tuning of the system. This is were heavy buffers, smaller gas ports and stronger extractor springs come in.

Fragmentation is an ammo issue not a weapon one. Truthfully that wasn't even considered until recently. SS109 sucks for fragmentation consistancy from a 20" barrel let alone a 16" shorter one. We can make ammo that performs though with those shorter barrels; see the 77gr mk262 and Horanday 75gr TAP.

I mean I can work up loads that will beat an AK to death or cause it to not run at all but is that the AK's fault? No. Can the gas piston kits fix certain issues, like a heavy wallet? Yes. They can also create new issues like broken carrier keys, buffer tube wear and tear, extra weight, etc. They can also rip off case rims of hot loads, soft cases, and filty chambers just as well as a DI gun.

In the end it's not the system, it's the tuning. The M4 is needed because it's shorter and more compact; it's updates took time because it cost money and time to do research and tune. We needed a shorter rifle right then, not a couple years down the line, so you got the 1st M4s which were shortened M16s. Years later the new issues were fixed. Ammo is still an issue but apparently we don't want to spend money on an upgrade when we also want/need to buy more ammo, guns, bombs, armor, etc.

All this opens the door to the "better" systems, which is to say systems that are better marketed; See: HK.
 
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http://www.youtube.com/watch?v=2LltApvOC0U

Mod edit: This is a video from POF-USA called "Problem Solvers". It's a POF commercial basically.

To the poster: Blind links are not good practice. People don't want to click on a link that goes who knows where. Please describe videos when you post links.
 
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A few things to consider. Marines are trained to shoot better at longer ranges than most other troops. They are more likely to use the extra range that comes from a full-length rifle.

I think that the M-4 makes the most sense for the cartridge. It's an intermediate-powered cartridge. I think it should be in a medium-sized rifle. If I wanted more range than an M-4 provides, I would really want a different weapon entirely.

As others have said, there is absolutely nothing wrong with the lethality of a 5.56 coming from any length barrel.
 
The only 'improvement' I could see over the original design is the placement of the charging handle. I very much prefer the H&K setup with the handle on the left and forward. But I can't see any feasible way to work it into the AR design. It is awkward to pull the charging handle towards your face with your weak hand. The original manual of arms trained to use your firing hand. It goes to show that nothing is perfect.

I see little advantage to piston systems. A correctly-made DI system works fine. One afternoon, I took a friends Bushy M-4 and cranked 500 rounds through it. No malfunctions. I oiled it a few times. The only time I have had an issued M-16 malfunction was with blanks.
 
I knew a guy who was in Somalia and said the targets would only go down only when they had about 5 rounds in them.
 
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There is/was nothing wrong with Stoner's design. Though, as technologies evolve, there may be room for improvements, tweaks, and learning what works best. Pistons are an option, but not neccessarily a net improvement.

Ammunition performance should not be confused with weapon function either. The weapon's job is to go bang and send a bullet at the target. Yes, the shorter the barrel, the less runway a bullet has to accellerate.

Ammo too has evolved with new projectiles. If the 5.56 doesn't do it for you, there are other cartridges available that work great in Stoner's DI system but perform better beyond the barrel.
 
Consider how many other makers copy portions of it. The barrel extension is the real genius, not DI. It's still just a piston gun - working more efficiently, but nonetheless, a piston gun.

If there is anything "wrong" with the Stoner design, it's that others who tinkered with it DIDN'T change what they should have - the straight mag well. Kalashnikov knew better, he designed the magazine in it's optimum configuration and made the gun fit it. COLT and the military changed the mag to a high capacity 30 rounder and have been trying to get it to work since 1969. Magpul finally got it best - but ANY tapered cartridge cannot feel optimally thru a straight section forced into the design. It should have been changed then, but there were too many other production faults to address when it was ramped up four fold.

Mags and ammo are the number one and two issues with malfunctions on the AR, for Stoners part, he did ok. Ask COLT and the DOD why they forced half baked alterations on the platform later.
 
This is like asking what is wrong with Henry Fords internal combustion engine. It was working fine in model T's why have they added all this stuff in cars today?? Answer things improve over time. You also have "mission specific" engines for different cars and trucks. Same with the ar15 platform.
 
mljdeckard said:
Well I knew a guy who was in Vietnam who saw guys walk after repeated .50 cal hits. Bullets aren't magical. There is no guarantee that any bullet will have any result on any target.
Click to expand...
Anybody that says he's seen people hit multiple times with a .50 cal walking around, has been watching too much TV.
 
DOESN'T IT CRIPPLE PERFORMANCE?
Click to expand...

No, it doesn't cripple performance; though it can reduce it in some circumstances. However, some feel the bonus provided by a shorter barrel (more rigidity, lighter weight, easier handling) outweigh that reduction in performance.

On the difference between a carbine DI and rifle DI, remember that this is measured in microseconds (millionths of a second). The only place you will see that difference in reliability is in long-term service life under hard use and at the extreme ends of the performance scale (full-auto, very hot rifles, etc.) and even that is debateable. When the military tested the M16A2 and M4 to destruction, they found that the M16A2 actually failed before the M4 due to the longer, less rigid barrel. So even though the M16A2 technically allows a bigger window for reliable function, the M4 still functioned reliably enough that the M16A2 burst its barrel before the M4.

On fragmentation, you have to remember that not all rounds rely on fragmentation for their effect - most notably, the new issue ammo for the Marines (Mk318 SOST) and Army (M855A1) are not dependent on yaw and fragmentation to achieve their results - so they can be more effective out of shorter barrels.

Even using FMJ rounds that do rely on fragmentation to be effective, most combat still occurs at ranges where even a 14.5" M4 with M855 ammo has the potential to fragment. And it isn't like the bullet turns into a Nerf arrow once it passes that magical threshold.

Like everything else in life, you pick the compromises that suit you best. Note that sometimes these benefits overlap as well - for example, somebody on an LE entry team isn't required to use FMJ ammo and will be fighting at ranges where the extra velocity won't be of as much benefit. However, they will definitely appreciate the faster handling and lighter weight of the shorter barrel.

As to gas pistons - you can tune a DI system to run well in any barrel length. The problem is when you do something to alter that equation (like add 6" of dwell time and increased backpressure in the form of a suppressor). Gas pistons can be an answer for some of these problems; but generally it tends to be a fairly specialized solution to a fairly specialized problem.

You've got the general facts straight. I think you just don't appreciate that the distinctions are fairly small. So small, that you can have a lot of good debates trying to quantify them (which is one reason it gets discussed on gunboards a lot, just like other small distinctions like 9mm vs .45, etc.)
 
I'm no expert, I readily admit.

In my research, I've found that a 14.5" carbine and a 62gr penetrator round seem less than ideal. I also tend to think that DI gas is less than ideal for a carbine.

I think that DI gas guns really, really shine in a set-up/role like a Mk12 rifle with Mk262 ammo. 18 inch free floated barrel with rifle length gas system, and an optical sight 3-10x, etc. You get all the accuracy of a bolt-gun, with all the speed of an automatic, and fantastic terminal ballistics. Similar set-ups tend to also dominate in 3-gun competitions. (Speed and accuracy competition)
 
It's only a narrow aspect of the question, but I found this:

http://neutrino-cannon.livejournal.com/378539.html

The gist of which is that it's really hard to tell if pistons improve anything because you end up having to switch out so many other parts it's not entirely clear that the improvement came from the switch to the piston.

According to Collector's Grade Publication's The Black Rifle, the gas system on the AR-15 isn't exactly what Stoner originally had in mind. The original AR-10s had the gas port and tube located on the left side of the receiver. It was relocated to the 12 oclock position where it is today by another engineer, not Stoner (it might have been Sullivan, I'd have to check). The buffer used to be a "return spring guide," that is, essentially a hollow piece of extruded aluminum tube. Now that piece has sliding weights. Add to that lots of alterations of the gas port diameter and location and you have a system that has diverged both in physical layout and operating parameters from the original design.
 
Good Lord, if everything were restricted to its original design intent, there would be very little room for innovation. I guess we should all go back to triangular handguards and full rifle buttstocks too. If you really think the cartridge gives up any measurable level of lethality within 300yds, you obviously never shot a critter with one. :rolleyes:
 
In the Volume 3, No. 1 , Spring 2011 issue of Small Arms Defense three writers address the 5.56 caliber.

One writer concludes there is no problem with the lethality of the NATO round.
One discusses intermediate calibers as a replacement.
The third mentions "urgent requests" from combat fields related to repeated failures, and lists 35 recommendations, findings, reports, soldier surveys, and field use requests dealing with widespread combat experiences and studies, and concludes by recommending consideration of a new system and caliber.

His citations are impressive, with multi-national origins.
No barroom anecdotes or Internet tales included. :)
I consider it a bit of an eye-opener, the guy obviously did his research.

On a side note in response to the original poster, not everybody uses or recommends a 14.5-inch barrel, and the barrels on my three carbines are all 16-inchers.
I don't particularly like dropping down that short, but for the sake of compactness I do. I still prefer my 20-incher.

Two weeks ago I worked with a piston-powered 5.56 pistol.
Chronographing it with several loads compared to a "control" 16-incher showed velocity losses of up to 900 feet per second.
The velocities through the 16-inch barrel were in themselves up to 170+/- FPS lower than with a 20-inch rifle also chronographed for another project.

Dropping from 20 inches to 16 CAN involve velocity losses of nearly 200 FPS, depending on the load & barrel.
In a caliber that depends on its velocity to be effective in a military or LE context, that loss can be significant.
Dropping down further in barrel length involves a further loss of velocity, and
a corresponding further drop in terminal effectiveness.
I'm not particularly comfortable with 16-inch velocities, but to get the most out of my carbines I've switched to Black Hills' 77-grain military load.

Below 16 inches I will not go.
Denis
 
Anybody [Strike]that says he's seen[/Strike] who believes people hit multiple times with a .50 cal [Strike]walking around[/Strike] can't possibly survive has been watching too much TV.
Click to expand...

There, fixed it.

To the OP:

Stoner didn't design the cartridge. Remington did.

The AR was originally a 7.62mm rifle.
 
The AR was originally a 7.62mm rifle.
Click to expand...
Just being picky but maybe you mean the AR-10 from which the AR-15 was developed.

AR just means it was an ARmalite design
AR-5 was 22 Hornet and the AR-7 was a 22LR for example. Some AR's are even 12ga shotguns and 9mm handguns (later design's).
Now the AR-1 was a 7.62x51 bolt action, so you are right just not in the way you intended.
 
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