Piston 223 vs Piston AR

[CTFish]

Can someone shed some light on piston guns for me?

For example, the KelTec SU-16 series is a piston gun. And the Mini 14 is a piston gun. But neither is an AR.

There are AR-15 piston guns (Ruger SR-556). And there are "AR" piston guns, like the AR-180B, which is not an AR-15 series.

WTF. Can someone point me to a website or something about these, with a list?

[senorlinc]

Not quite sure what you are asking but i will attempt to answer this in bits and pieces

AR is for Armalite Rifle

15 is the mnodel number

Today, though, "AR15" has become a colloquialism for semi auto rifles based on Stoner's design

the traditional AR15 cycles using direct impingement. this means that gasses expelled by a fired cartridge are channeled directly (via gas tube) to cycle the bolt carrier. this syetem is used in most rifles such as bushmasters, dpms, colt, or noveske

a piston rifle works similarly however instead of the gasses directly pushing the bolt carrie rdirectly they are passes to a piston which then cycles the bolt. this system is used by some of the lastest incarnations of the stoner rifle such as the HK416, FN SCAR, LWRC's rifles and POF (bushmaster and colt have piston rifles too). AK style rifles use a gas piston system as well.

the kel tec su16 and mini 14 rifles use a gas piston and are .223 caliber however they are not Stoner type rifles


piston = system that cycles bolt carrier

AR = rifle based on Eugene Stoner design

.223 = caliber of cartridge

a rifle can be one or all of the above

[mojo]

Not quite sure what you are asking but i will attempt to answer this in bits and pieces

AR is for Armalite Rifle

15 is the mnodel number

Today, though, "AR15" has become a colloquialism for semi auto rifles based on Stoner's design

the traditional AR15 cycles using direct impingement. this means that gasses expelled by a fired cartridge are channeled directly (via gas tube) to cycle the bolt carrier. this syetem is used in most rifles such as bushmasters, dpms, colt, or noveske

a piston rifle works similarly however instead of the gasses directly pushing the bolt carrie rdirectly they are passes to a piston which then cycles the bolt. this system is used by some of the lastest incarnations of the stoner rifle such as the HK416, FN SCAR, LWRC's rifles and POF (bushmaster and colt have piston rifles too). AK style rifles use a gas piston system as well.

the kel tec su16 and mini 14 rifles use a gas piston and are .223 caliber however they are not Stoner type rifles


piston = system that cycles bolt carrier

AR = rifle based on Eugene Stoner design

.223 = caliber of cartridge

a rifle can be one or all of the above

Great reply!!

[CTFish]

BTW I found this nice animation of piston vs DI.
http://www.armytimes.com/projects/fl...02_20_carbine/

[synergy]

Colt doesn't have a piston rifle out.

They're mostly over-hyped, and really only worth looking at if you run a short barrel, with a suppressor, in full auto.

The whole "cleaner action" thing is over hyped too, as you can go 1k+ rounds in AR's without cleaning them.

If you want longer parts life, shoot a mid length gas system.

They are proving to be a headache for a number of companies, and most knowledgeable shooters are staying clear of them, when it comes to guns they trust with their life. Some piston rifles are better than others, for example the HK-416. But keep in mind, part of why that gun runs so well is because it's an HK, not because it's piston operated.

I'll quote this from a BTDT guy over on another forum (long time NCO with the 75th Rangers). He posted this in response to comments made by the author of Black Rifles, Chris Bartocci. It's a bit of a history lesson, too.

Posted 04 March 2007 18:27 04 March 2007 19:27

I've decided to pick apart Bartocci's fundamentally flawed response. As his tone describes...HE IS A COLT AFICIONADO AND HAS DRANK THE COOL AID!!!


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This is very much the propaganda that H&K has been pushing since they came up with the idea that the direct gas system was flawed and they had the century old magical piston system from which they claim is new.

HK was not who came up with the hypothesis that the Direct Drive Impingement System (DDIS) in the M16 family of was flawed. That was a discovery made in the late 70"s early to mid "80's when increased usage and proper application of the M16 family of weapons was pioneered by US Military SMU's and other Elite Units of the worlds forces--i.e.M16A1, CAR-15,GAU-15, XM177E1. It was first voiced by small weapons experts in the US. military community at that time who were finding that parts wear out and service life was severely impacted by the increased heat volume in the chamber induced by the DDIS.
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After the "bugs" were worked out and the new M16A1 came online, the reliability increased and troops who went to Vietnam after 1969 encountered little trouble.
The point of this is that the piston driven AR is an old concept that the Army rejected in favor of the direct gas system currently in use in the M16. They found no significant increase in reliability due to the use of the piston system.

Again he is wrong here. What they found was that there was no significant performance in the form of the currently available short stroke piston technology known of at that time. Additionally, there is controversial information regarding Colt's and the Army's diligence in their approach at improving the already available piston technology. In other words, the current piston technology available was limited at the time (as attested to by the existing piston type weapons: AK47, M14, M1 Carbine to name a few; considered rudimentary at best) and there was no desire exhibited by the Military and or Colt to dedicate a concerted effort to improve the existing piston technology of that time.
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Some additional pertinent information is that the reason for the SCAR program had much to do with SOCOM wanting to be their own project manager and have the ability to make changes to the weapon specific to them. This is something they could not do with the M4A1.

WRONG!!! Crane and USSOCOM are the PM for modifications to the M4A1--in the form of PM-SP. Look at the SOPMOD Kit--Special Operations Peculiar Modification Kit designed and implemented by USSOCOM/Crane--I know I was the 75th Ranger Regimental Force Mod NCO in 1998/99 who was involved in that developmental MODIFICATION project.
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Those who would later go on record calling this weapon flawed because the 6 pound carbine would not function as a high volume fire light support belt fed weapon they required.

WRONG AGAIN!!! The TIER'ed units/SMU's never used or desired to use the M4A1 as a "high volume fire light support belt fed weapon". They used the weapon as it was intended. Additionally, the M4A1 program was initiated in earnest after "Operation Just Cause"/1989, when the Speciality units--SFOD/Rangers/ST6--complained that we needed a more compact system that met the same employment criteria as the M16 family. There was much involvement by those units in the M4A1's development. Some fleas were discovered at that time, but again, timeliness overcame further development because Colt advised the Government that further development would require more time and money. They went on record as assuring the end user that the weapon was ready for prime time as is and stated that it was good enough to take into combat at that time. Colt's complacency later became known in the firearms industry as the mindset of "Coltitis"--it's good enough as is--later echoed by larger entities (the USAIC, TRADOC for example).
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The Colt piston system rifle is the ONLY piston driven M4-platform weapon to ever complete and official SOCOM trial, not the HK416.

WRONG AGAIN. the M4 piston (known as the M5) failed the "over the beach" portion of the test thus failing the SCAR trials. It was the longest performing M4 platform in the SCAR trials at best. Further, it sounds to me like he is selling Colts rifles for them the same way he's inferring Army Times is doing HK's bidding!!!

Anyway, here's another BTDT guys take on the piston fad:

The only problems I ever saw with our A2, in a boat company... (if you dont understand what that entails environment wise, beat your face) were broken ejection port cover springs, the rare cracked gas tube and excessive windage because someone did something stupid with their weapon. The weapons got sugar cookied pretty hard, and it took kickstarting and squirting water from a camelback into the bolt at times to free it up... Still went bang. An HK416 would be just as f*cking jammed up in that kind of use. They want to impress me, dip that rifle in the tank first (saltwater) then bury the f*cker and lets see how quickly that f*cker gets up and running. Hell, screw the control and do it at the tide line. Let Murphy and his mistress Mother Nature work on the gun for a few seconds. Get that handy vented rail full of sand and kelp, what have you... Good luck freeing up that piston. Keep in mind, a piston has more moving parts to foul up. Theres an advantage to DI guns, that is never brought up. There are no other crucial moving parts outside the receiver other than the selector and trigger.

Sure the weapons got dirty, but they still f*cking worked. I call BULLSH*T on all this negative hype that these Hun bastards are stirring up. Substitute an armory M16 or M4 into that 416 video, close the cover and bury it, shovel sand over the gas tube, and dunk the rifle then sling the water out of the bore and fire it... and the only thing that I wouldnt advise doing is handling the bolt after going cyclic.

HKs trying to get political by stirring up the sh*tpot like politicians did over the body armor issue. Sure this has merit, but if the 416 is the sh*t like they say it is, then they need to f*cking shut up and it'll sell itself.

Check out m4carbine.net for plenty of reports of piston rifles choking, and exhibiting accuracy issues.
Here's a place or two to start:
http://m4carbine.net/showthread.php?t=29852
http://forum.pafoa.org/rifles-42/656...tml#post823107

IIRC, Pat Rogers is doing/ recently did a test on the 416 and some other piston guns. From what I hear, it's nothing spectacular, at least so far.
http://www.m4carbine.net/showthread.php?t=37595