Piston vs Impingement?

TRaTSeRiF said:
I like DI guns for competition use. Very smooth-shooting and light. I've found them to be primadonas compared to piston guns though (not AR, but SKS and VZ). For a competition gun, that's not a problem as it stays clean and doesn't fire more than 300 or so rds in a range session. Shoot about 500 and the effect of those dirty gasses blowing directly at your BCG will be felt.
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Not in my experience and the way I shoot 500 rounds is more brutal and punishing than just about anything else.


Gunnerlove said:
The round count required to generate cook offs in piston guns is the same as DI guns which is why according to the US IAR program the number of full auto rounds required to generate a cook off is the same for the M4 as the 416. Bolt face heat is chamber heat. But hey keep the cool running myth alive.
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I'd like to hear more about AR's getting hot enough to cook off rounds. I have done a number of 400-500 round FA tests and have never experienced a cook off. We got the gun to the point where the operator had to wear gloves because the forend and upper were too hot to touch. Even the buffer tube would get hot to the touch. We had the gas tube glowing cherry red to the point where I was concerned it would explode. Never experienced a cook off though.
 
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Suputin said:
Not in my experience and the way I shoot 500 rounds is more brutal and punishing than just about anything else.




I'd like to hear more about AR's getting hot enough to cook off rounds. I have done a number of 400-500 round FA tests and have never experienced a cook off. We got the gun to the point where the operator had to wear gloves because the forend and upper were too hot to touch. Even the buffer tube would get hot to the touch. We had the gas tube glowing cherry red to the point where I was concerned it would explode. Never experienced a cook off though.
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WOW
here you go
 
Unless it's under 10" or an HK MR223 (just cause I like em) I'd go DI, preferably a 14.5" barrel with a mid length gas system like the ones BCM is making. Either that or a 12" Noveske for something a bit shorter(starting to think it's the ideal SBR length). I've got 3 DD's (M4A1,MK18,V7) and my brother has a V1 and a Colt 9620, we haven't had issue's with any of them. Go DI unless it's super short and the reliability would benefit from a piston system.
 
metal doesnt really change its integrity until it reaches red hot. even then, once its cooled off its back to normal. if you really shoot the gun til its red hot on semi at every range sessions, youd be wearing down the gun and barrel regardless of what type of gas system you shoot. even then, a DI gun is cheaper to replace all the worn parts. gas tube, gas ring. and thats pretty much it. given that bolt face temperature is same as chamber temperature .the bolt on a piston gun would have just as much bolt wear as a DI if you shot the same amount of rounds out of the two.

the lightness of a DI gun benefits me more shot after shot, at every target that i acquire ,over that one malfunction that i might encounter thousands of rounds later that a piston gun might have prevented..... even then. a piston gun isnt guaranty reliable.
 
well some people bring in cooking off of live round into semi auto world. lol.

its like worrying about your honda civic sucking in so much air you need two spark plugs like a 5000 hp dragster.
 
deagle2008 said:
TDC said:
Dirty is immaterial. If the gun runs then go with it. Have a look at the filthy 14 legacy. 19000 rounds plus without cleaning and no issues. Piston is indeed snake oil that has yet to be proven a substantial improvement over di. The whole hot bolt bs is just that bs. Your bolt hardly gets warm and there's no reason to touch it.

I dont touch the bolt but more heat means more tear and we both know DI bolt does get really hot during rapid firing. I dont know you but I assume you have a PD ar and ur not just talking outta ur ass. But if you dont have it and have never experienced one you shouldn't talk.
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You should learn to use some deductive reasoning. I don't own a pd ar because they're over priced over weight snake oil. I have shot a bit with a couple pd guns and they were no better than a quality di gun.

Extreme heat is an issue, the heat most will experience shooting an ar is trivial. Having personally fired 7 plus 30 round magazines in less than 15 minutes I can tell you the heat is not a concern nor is the "dirty" gun syndrome so many go on about. This was done late on the second day of a course and the range was wet and sandy. The only rifles that went down were the poorly lubricated ones.

Pws makes a great pd gun but its expensive, heavy, and includes extra parts. The ruger pd gun suffers from carrier tilt more so than others which creates its own issues. The aftermarket kits are junk. Another clue would be the absence of pd guns in use by top name instructors. I don't know of any who have dumped their di gun for a pd gun. You'd think if pd were so much better the big names would have switched.

At the end of the day it has more to do with the quality of the rifle in question and how well it is maintained. A quality di gun with proper lube and maintenance will serve you well and at a lower cost.

Tdc
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I look at the DI vs piston debate like this: A Piston is like a condom - it's there as a barrier to protect you from the dirty stuff. OTOH, maybe you don't need a condom if you know how to keep your weapon clean.
 
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deagle2008 said:
WOW
here you go
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Nice. Never seen that before.



deagle2008 said:
now we all know we dont shoot FA or like the videos above but you get the point about DI VS Piston
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Except I would make the argument that those cookoffs are related to chamber heat which would be unaffected by a piston system.

Not to mention that no civilian user of an AR in this country will ever get their rifle that hot, making the entire argument moot.
 
I bought a stag 8t last year. The piston action wasn't really the big feature for me, I was more into the diamondhead accessories that came with the rifle. That said, I have had zero issues so far.
 
Wow so much hate on piston Ar-15 get a life guys.

If you are happy with you DI or piston ar-15 then its the only thing that matter.

I have a piston ar-15 and my father have a DI ar-15 and both run great and are fun to shoot.
 
So , DI is more popular, both seem to be good. DI = light and dirty- Piston= heavy and clean. Hmmm .. What a dilemma ...:) I like the DI, but either way ,either one sounds good. Now to find one that can shoot the nuts off a fly at a 100 yards ... And don't cost a fortune..
 
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