PISTON AR10 CONVERSION

375snot

375snot

Full Member
Full Member
Minuteman
Feb 10, 2010
10
1
35
#1
Has anybody ever seen a conversion from gas operation to piston that would work in a DPMS SASS?

I hate gas operation and how quickly they get dirty.

I'd rather not spend a pile on a new POF upper or something crazy like that on my budget?
 
#2
Re: PISTON AR10 CONVERSION

If you hate gas operation, then you should get an HK-91 since it's delayed recoil blowback.

I think the term you're looking for is "Direct (Gas) Impingement" since a piston system is also "Gas Operated".

I still don't get the obsession with piston conversions. On traditional direct impingement AR's all operating parts are in a direct line with the bore. It is theorized that this is one of the reasons that AR's are so accurate. There's no outside influences off the center of the bore potentially effecting the harmonics of the barrel.

I've run over 1k rounds through an AR without cleaning and no ill effects. Heck, that's pretty much my cleaning cycle. A toothbrush, CLP and a rag is all you need. It doesn't need to be spic and span.
 
#3
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I still don't get the obsession with piston conversions. On traditional direct impingement AR's all operating parts are in a direct line with the bore. It is theorized that this is one of the reasons that AR's are so accurate. There's no outside influences off the center of the bore potentially effecting the harmonics of the barrel.

I've run over 1k rounds through an AR without cleaning and no ill effects. Heck, that's pretty much my cleaning cycle. A toothbrush, CLP and a rag is all you need. It doesn't need to be spic and span. </div></div>

Dern Tootin.

Clean enough is clean enough. I shoot badly enough as it is without adding extra (extremely overpriced and insufficiently time tested!)moving parts to my shootin irons!
 
#4
Re: PISTON AR10 CONVERSION

I'm not sure what you do for a living but I've had a gas operated m4 seize up on me when i needed it to run and it just had a little dust and tw25 in it. Needless to say that gas operation put a bad taste in my mouth.


All i wanted to know was whether or not anybody knew of a conversion.
 
#5
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 375snot</div><div class="ubbcode-body">I'm not sure what you do for a living but I've had a gas operated m4 seize up on me when i needed it to run and it just had a little dust and tw25 in it. Needless to say that gas operation put a bad taste in my mouth.


All i wanted to know was whether or not anybody knew of a conversion. </div></div>

I always see this stuff on the internet, but no one that I actually know lost confidence in the M4 from poor performance. Stick to bolt guns if "gas operation" isn't your thing, as piston guns are also gas operated.
 
#6
Re: PISTON AR10 CONVERSION

Adams Arms and other companies are working on piston coversion kits for the AR-10/LR308 type rifles. They are not available yet and I don't know what the timeframe for completion/marketing might be at this point.
 
#7
Re: PISTON AR10 CONVERSION

I built a Piston AR15, and all that means is I have to clean other parts. Piston systems arent the end all that many people seem to think they are. I have had more problems with my Piston AR than any other gun I own. I have a Bushmaster, and I just had to take the thing apart last night for another overhaul.

Everyone thinks piston systems dont need cleaning, but they do! The gas ports on my piston cylinder were half plugged with carbon, and this caused too much pressure on the system. The piston came out of the cylinder. Other systems are not built like the bushmaster, but they are far from maintenance free. Inside the cylinder was packed with carbon, and that raised the pressure as well.

Every 500 rounds or so from now on I have to check the gas ports to make sure they are open. Cut that in half if you run suppressed. I like the piston system, but the marketing hype is far from reality.
 
#8
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 375snot</div><div class="ubbcode-body">I'm not sure what you do for a living but I've had a gas operated m4 seize up on me when i needed it to run and it just had a little dust and tw25 in it. Needless to say that gas operation put a bad taste in my mouth.


All i wanted to know was whether or not anybody knew of a conversion. </div></div>

Your point, and inquiry, are valid and the market place has usually responded to problems, both real and imagined, along the lines of those you point out in your experience.

My point was that the curent wave of piston modifications for current DI AR's is still in its infancy and may yet prove to be a very expensive lesson for many of those who choose to make the swap. Nor is it the unfettered solution it is advertised to be. I'd prefer to see which conversion or providor of said conversion stands the test of time before I pony up several hundred hard earned clams. JMO.

As I know of no one making one for the Armalite AR-10, the short answer to the question could have been answered more succinctly.

My livlihood typically requires cordless drills, table saws, circular saws, Jig saws, saw-zalls, levels, squares, tape measures, hammers, other hand tools, occasional brute strength, ringing ears, fucked up hands and amazing skill!
laugh.gif


That said, it isn't simply my singular opinion that many people spend way too much time and money on the newest gadgets or low return drudgery.

Good luck to you and I hope your problems get solved to your satisfaction.
 
#9
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 375snot</div><div class="ubbcode-body">I'm not sure what you do for a living but I've had a gas operated m4 seize up on me when i needed it to run and it just had a little dust and tw25 in it. Needless to say that gas operation put a bad taste in my mouth.


All i wanted to know was whether or not anybody knew of a conversion. </div></div>

Don't use TW-25 in an AR. AR's aren't supposed to be lubed with grease. Grease attracts dirt and other fouling. Only lube with grease if the weapon's manual calls for it.

Use CLP. I've had a buddies AR-10 not run because he was using a random other gun oil. I got him to use CLP, and it ran like a top.

I'd say that any AR that fails, but was properly lubed and is using high quality ammo and mags, has some manufacturing defect. Either that or it's not properly broken in. I wouldn't trust any firearm with my life until it's had at least 500rds through it.
 
#10
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: queequeg</div><div class="ubbcode-body"> <div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I still don't get the obsession with piston conversions. On traditional direct impingement AR's all operating parts are in a direct line with the bore. It is theorized that this is one of the reasons that AR's are so accurate. There's no outside influences off the center of the bore potentially effecting the harmonics of the barrel.

I've run over 1k rounds through an AR without cleaning and no ill effects. Heck, that's pretty much my cleaning cycle. A toothbrush, CLP and a rag is all you need. It doesn't need to be spic and span. </div></div>

Dern Tootin.

Clean enough is clean enough. I shoot badly enough as it is without adding extra (extremely overpriced and insufficiently time tested!)moving parts to my shootin irons! </div></div>


If you shoot suppressed you might understand.
 
#11
Re: PISTON AR10 CONVERSION

Forgot to mention that i shoot 100% suppressed.

ALL of the carbon from the round is 100% trapped by the can and 1 shot of a nonpiston rifle completely fouls the rifle.
 
#12
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Salmonaxe</div><div class="ubbcode-body">

Don't use TW-25 in an AR. AR's aren't supposed to be lubed with grease. Grease attracts dirt and other fouling. Only lube with grease if the weapon's manual calls for it.

Use CLP. I've had a buddies AR-10 not run because he was using a random other gun oil. I got him to use CLP, and it ran like a top.

I'd say that any AR that fails, but was properly lubed and is using high quality ammo and mags, has some manufacturing defect. Either that or it's not properly broken in. I wouldn't trust any firearm with my life until it's had at least 500rds through it. </div></div>

And CLP does not attract dirt? I have had much better luck with grease than CLP. My whole bolt is a dirt disaster when I spray CLP all over. If I just grease a few spots it stays much cleaner and runs just as long.
 
#15
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 375snot</div><div class="ubbcode-body">Forgot to mention that i shoot 100% suppressed.

ALL of the carbon from the round is 100% trapped by the can and 1 shot of a nonpiston rifle completely fouls the rifle. </div></div>

Not trying to be a smart-ass and I'm asking this becuase I simply don't know and I'm on the verge of suppressing a M1A so have studied this a little bit...

Suppressed fire regardless of all the manufactured reasons to justify it was never intended but for one thing...to conceal your position. Given this, why does anyone shoot suppressed 100% of the time knowing the stresses it puts on a weapon, ANY weapon whether bolt or gas that needs to function flawlessly when you need it most, then complains about the natural consequences of this type of use?

I want a suppressor so in the unlikely event I ever need to conceal my position while shooting at someone I'll be able to get that one shot off that matters including any follow-ups with a weapon that I know that hasn't been abused.

Am I missing something? It's like owning a race car, treating it like one, then complaining about having to rebuild the engine every few races.
 
#16
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: TheOneTwo</div><div class="ubbcode-body">If I just grease a few spots it stays much cleaner and runs just as long. </div></div>

I use grease on both my AR and SASS. A light smear(not gobs) in exactly the right spots with a Q-Tip makes for a much smoother action. Just the wear marks on the BCG, and the charge handle groove is all you need. Everything else gets oil.
 
#17
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: queequeg</div><div class="ubbcode-body"> <div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I still don't get the obsession with piston conversions. On traditional direct impingement AR's all operating parts are in a direct line with the bore. It is theorized that this is one of the reasons that AR's are so accurate. There's no outside influences off the center of the bore potentially effecting the harmonics of the barrel.

I've run over 1k rounds through an AR without cleaning and no ill effects. Heck, that's pretty much my cleaning cycle. A toothbrush, CLP and a rag is all you need. It doesn't need to be spic and span. </div></div>

Dern Tootin.

Clean enough is clean enough. I shoot badly enough as it is without adding extra (extremely overpriced and insufficiently time tested!)moving parts to my shootin irons! </div></div>well yes but its more with the lub used for many reasons likes of Mobil 1 synthetic oil which doesn't carbon up as easily ,this is key to the picture vs. natural oil based aka flash burn = carbon build up with powder residua ....
 
#18
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 375snot</div><div class="ubbcode-body">Forgot to mention that i shoot 100% suppressed. </div></div>

I would like to update mine for same reason.
Amount of carbon inside reciever doubles or triples with can.
For example, shiny brass turns into completely flat gray with just one shot. Even case bottom.

Annoying, and messy to even touch before reloading/cleaning.
 
#19
Re: PISTON AR10 CONVERSION

As far as keeping the AR lubed and running. I was once read that grease is for "farm machinery" the M1 and hence the M14 was built for farm boys. Jets and race cars use lubr oil snd since the M16/AR was built by a aircraft designer use high tech oil. KEEP IT WET!! Alot of old timers say in the dust dry is better but sand still gets in and dry sand is just grit. At least if there is alot of light hightech lube the grit flows and moves. Not a great situation but it was it is.
 
#20
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BattleAxe</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 375snot</div><div class="ubbcode-body">Forgot to mention that i shoot 100% suppressed.

ALL of the carbon from the round is 100% trapped by the can and 1 shot of a nonpiston rifle completely fouls the rifle. </div></div>

Not trying to be a smart-ass and I'm asking this becuase I simply don't know and I'm on the verge of suppressing a M1A so have studied this a little bit...

Suppressed fire regardless of all the manufactured reasons to justify it was never intended but for one thing...to conceal your position. Given this, why does anyone shoot suppressed 100% of the time knowing the stresses it puts on a weapon, ANY weapon whether bolt or gas that needs to function flawlessly when you need it most, then complains about the natural consequences of this type of use?

I want a suppressor so in the unlikely event I ever need to conceal my position while shooting at someone I'll be able to get that one shot off that matters including any follow-ups with a weapon that I know that hasn't been abused.

Am I missing something? It's like owning a race car, treating it like one, then complaining about having to rebuild the engine every few races.</div></div>

Shooting suppressed allows you to have the benefits of recoil abatement, minimal flash and hearing safe shooting (or close to it).

So, if you have ever used a muzzle brake, flash hider or hearing protection, then that is why you would add an item that combines the effects of all three 100% of the time.

People often report that despite harmonic change, their groups usually tighten with the same load that they were using when using a suppressor. This is because our natural flinching and jerking is minimized because the expected boom and recoil is also minimized.

That said, shooting suppressed is dirty. Even with my Adams piston, my chamber dirties in my M4 much quicker than without a suppressor in a direct impingement system.

Additionally, piston setups like the POF and LWRC in .308 have regulators that allow adjustment of how much gas is used to cycle the action, minimizing unnecessary damage to your bolt and extractor and helping reduce vibration that can detract from accuracy. Since I added my Adams Arms piston kit to my suppressed M4, the group average has dropped from 1.5 MOA to 1 MOA with the same ammo. I can also completely shut off the gas and operate the gun as a manual action for maximum cleanliness and stealth (no flying brass to give away a position).

So basically a short stroke piston on an AR system will enhance the number of accurate rounds you can shoot between cleaning versus a direct impingement system (with or without a suppressor).

Shooting suppressed is not perfect, but being able to communicate with my shooting partner without yelling and playing charades, as well as minimal recoil and flash is why I shoot suppressed. YMMV.

I look forward to the Adams Arms .308 due late 2010 or early 2011.
 
#21
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: buffetdestroyer</div><div class="ubbcode-body">Shooting suppressed allows you to have the benefits of recoil abatement, minimal flash and hearing safe shooting (or close to it).

So, if you have ever used a muzzle brake, flash hider or hearing protection, then that is why you would add an item that combines the effects of all three 100% of the time.

People often report that despite harmonic change, their groups usually tighten with the same load that they were using when using a suppressor. This is because our natural flinching and jerking is minimized because the expected boom and recoil is also minimized.

That said, shooting suppressed is dirty. Even with my Adams piston, my chamber dirties in my M4 much quicker than without a suppressor in a direct impingement system.

Additionally, piston setups like the POF and LWRC in .308 have regulators that allow adjustment of how much gas is used to cycle the action, minimizing unnecessary damage to your bolt and extractor and helping reduce vibration that can detract from accuracy. Since I added my Adams Arms piston kit to my suppressed M4, the group average has dropped from 1.5 MOA to 1 MOA with the same ammo. I can also completely shut off the gas and operate the gun as a manual action for maximum cleanliness and stealth (no flying brass to give away a position).

So basically a short stroke piston on an AR system will enhance the number of accurate rounds you can shoot between cleaning versus a direct impingement system (with or without a suppressor).

Shooting suppressed is not perfect, but being able to communicate with my shooting partner without yelling and playing charades, as well as minimal recoil and flash is why I shoot suppressed. YMMV.

I look forward to the Adams Arms .308 due late 2010 or early 2011. </div></div>

Good explanation and I can see that side of it now. For me though there's a visceral component to shooting that I like. Recoil and noise is part of the experience of it I suppose. I'll likely confined my suppressed fire to the M1A and only occasionally.
 
#22
Re: PISTON AR10 CONVERSION

375snot said:
I'm not sure what you do for a living but I've had a gas operated m4 seize up on me when i needed it to run and it just had a little dust and tw25 in it. Needless to say that gas operation put a bad taste in my mouth.


All i wanted to know was whether or not anybody knew of a conversion.
Click to expand...

You apparently don't know much about firearms- as stated before, a piston system IS GAS OPERATED. We're not asking you to say "I want a short-stroke gas piston conversion". Or "I'd like to convert it to a long-stroke gas piston/op rod system like the AK" (not available btw). Just simply to stop referring to direct impingement as if it is gas operated while a piston system is not. They are both gas guns, just different operating principles.

Anyhow, the Army conducted some tests recently as mandated by congress before they could proceed with anymore M4 orders. What they found was that the XM8 and HK416 outperformed the M4 in dusty environments- but only by a VERY small number, and this is after firing, as I recall 10k rounds from each gun without the benefits of a full cleaning.

DI guns are plenty reliable when maintained and lubr
 
#23
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DP425</div><div class="ubbcode-body">
Anyhow, the Army conducted some tests recently as mandated by congress before they could proceed with anymore M4 orders. What they found was that the XM8 and HK416 outperformed the M4 in dusty environments- but only by a VERY small number, and this is after firing, as I recall 10k rounds from each gun without the benefits of a full cleaning.

DI guns are plenty reliable when maintained and lubr </div></div>


Link?
 
#24
Re: PISTON AR10 CONVERSION

I agree that the piston is unnecessary for a large number of civilian AR15's out there. They are reliable and not typically subjected to the kind of environments and conditions that a piston system might have an edge.

However, full auto fire and suppressed fire is where I see a definite advantage, as well as in crappy dusty or muddy environments.

Regarding the dust test check out http://www.armytimes.com/news/2007/12/army_carbine_dusttest_071217/

<span style="font-style: italic">Officials tested 10 each of the four carbine models, firing a total of 60,000 rounds per model. Here’s how they ranked, according to the total number of times each model stopped firing:

• XM8: 127 stoppages.

• MK16 SCAR Light: 226 stoppages.

• 416: 233 stoppages.

• M4: 882 stoppages.</span>

This works out to 1.47% failure rate in the M4 vs. .39% failure rate in the HK416. Neither is horrible, but if I had to bet my life 100 times, I would go with the piston.

Edit: Also important to note that magazine stoppages were responsible for 239 of the 882 stoppages. I would guess that the two HK's used proprietary HK mags ($40-$50 each in the civilian market). Even taking that out, you are still over 1% failure rate that is weapon related. I am wondering if they did the test with PMags, would it still be as bad?
 
#25
Re: PISTON AR10 CONVERSION

Thanks buffetdestroyer. I think a few key things can be taken from the test:

-As you stated, it's safe to assume they used the issue mags for the M4 for the 416 and SCAR, HK and FN designed mags. Not sure it's safe to assume anything for the XM8 since it's a gun built by HK, but under contract for the Army and without production contracts. Could go either way. Anyhow, with a better mag, I'd almost bet you could eliminate mag stoppages.

-The firing table was far beyond what you'll see for an actual firefight, so you'll have the effects of lack of cleaning building up during those 1200rd periods. I'd be interested to know when the majority of stoppages occurred or if it was evenly spaced throughout the testing.

-Lubrication used would have almost certainly been CLP- I'm curious what a less dust attractive lubrication would have done.

-Remember, these guns were put in a dust chamber which I would imagine to be like one of the MASSIVE dust storms you get in Iraq two-three times a year. This is far from the normal operating environment. And actually, it's unlikely you'd be doing much fighting with such a situation.


Anyhow, it is apparent that these guns performed more reliably, but it wasn't really a significant enough difference to warrant deviating from a DI set-up for a home user, and it's questionable if it would make sense to immediately ditch the M4 in favor of a different system that is only about 0.7% more reliable when magazine deficiencies are taken out of the equation. A graduated, slow replacement option would be a better route to go- it's not an urgent need replacement.
 
#26
Re: PISTON AR10 CONVERSION

The outcome speaks for itself... they stayed with the M4.

I have nothing bad to say about the direct impingement system of the AR or M4. It has a long track record and 89% approval from our troops.

In specialized situations (like when the weapon is suppressed), the piston does have an advantage. So for us suppressor guys, it makes sense to go the piston route. For everyone else, if it makes you happy, then add as much as you can carry to your AR15! If not, then that's great too. As a note, I would carry an AR with confidence over a Mini 14 any day of the week because of accuracy, ergonomics and adaptability.
 
#27
Re: PISTON AR10 CONVERSION

I have two DI and five piston ARs. I am sure that if you just go to the range pop a few rounds put your rifle back and go back a few months later, then there is no issue with DI. But i have taken my rifles to courses and put them thru the paces and the pistons always come on top when you really stress them.

Last class i did was with Chris Costa and Magpul Dynamics and i took my Noveske 14.5" which is DI and LWRC which is piston obviously. Now let me say that i love my Noveske. But we were doing a few drills that required 8-10 mag changes. We were doing double taps while moving from target to target. We had a mag in the rifle and 3 mags on us. When we finished we ran back to the table and grabbed four more mags and rejoined the group.

I can tell you that although i had never experienced a malfunction with my Noveske, after about the 5th mag dump, my bolt came to a complete stop. It had gotten so hot that it cooked off any oil that was on there. That definitely took me out of the drill/fight. I grabbed my LWRC and continued and used it for the rest of the 6hr class without any oiling and it never missed a beat.

With POF/LWRC you can do three or four mag dumps, pull the pins, pull out the bolt and hold it in your hands and it is barely warm. Try that with a DI bolt and you will have 3rd degree burns. If you dont think that extra heat and carbon thrown back in the action has no effect or stress on the operation of the rifle then i dont know what else to say.

Once again, for 95% of shooters it really doesnt matter cause they dont shoot their AR 200-300 rnds a year let alone in a few minutes. But if for whatever reason you want a rifle that goes bang every time regardless of conditions then i would choose the piston.
 
#28
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: buffetdestroyer</div><div class="ubbcode-body">I agree that the piston is unnecessary for a large number of civilian AR15's out there. They are reliable and not typically subjected to the kind of environments and conditions that a piston system might have an edge.

However, full auto fire and suppressed fire is where I see a definite advantage, as well as in crappy dusty or muddy environments.

Regarding the dust test check out http://www.armytimes.com/news/2007/12/army_carbine_dusttest_071217/

<span style="font-style: italic">Officials tested 10 each of the four carbine models, firing a total of 60,000 rounds per model. Here’s how they ranked, according to the total number of times each model stopped firing:

• XM8: 127 stoppages.

• MK16 SCAR Light: 226 stoppages.

• 416: 233 stoppages.

• M4: 882 stoppages.</span>

This works out to 1.47% failure rate in the M4 vs. .39% failure rate in the HK416. Neither is horrible, but if I had to bet my life 100 times, I would go with the piston.

Edit: Also important to note that magazine stoppages were responsible for 239 of the 882 stoppages. I would guess that the two HK's used proprietary HK mags ($40-$50 each in the civilian market). Even taking that out, you are still over 1% failure rate that is weapon related. I am wondering if they did the test with PMags, would it still be as bad?</div></div>

Did you also read the part where they said that this test was not designed to replicate real-world conditions? Further, did you notice that this was actually the 3rd dust test they conducted, and in the second test, which they repeatedly reference, the results were significantly better for the M4.

Straight from the test report:

"Significant difference between EDT II and EDT III in results for M4
296 stoppages (EDT II) vs 863 stoppages (EDT III)
This indicates that test protocol may not be repeatable
Interaction of technical variables not fully understood at this point in time"

It's amazing how people are always so quick to bring this dust test up, but don't seem to bother to actually understand what the test was about.
 
#29
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: alpha6164</div><div class="ubbcode-body">I have two DI and five piston ARs. I am sure that if you just go to the range pop a few rounds put your rifle back and go back a few months later, then there is no issue with DI. But i have taken my rifles to courses and put them thru the paces and the pistons always come on top when you really stress them.

Last class i did was with Chris Costa and Magpul Dynamics and i took my Noveske 14.5" which is DI and LWRC which is piston obviously. Now let me say that i love my Noveske. But we were doing a few drills that required 8-10 mag changes. We were doing double taps while moving from target to target. We had a mag in the rifle and 3 mags on us. When we finished we ran back to the table and grabbed four more mags and rejoined the group.

I can tell you that although i had never experienced a malfunction with my Noveske, after about the 5th mag dump, my bolt came to a complete stop. It had gotten so hot that it cooked off any oil that was on there. That definitely took me out of the drill/fight. I grabbed my LWRC and continued and used it for the rest of the 6hr class without any oiling and it never missed a beat.

With POF/LWRC you can do three or four mag dumps, pull the pins, pull out the bolt and hold it in your hands and it is barely warm. Try that with a DI bolt and you will have 3rd degree burns. If you dont think that extra heat and carbon thrown back in the action has no effect or stress on the operation of the rifle then i dont know what else to say.

Once again, for 95% of shooters it really doesnt matter cause they dont shoot their AR 200-300 rnds a year let alone in a few minutes. But if for whatever reason you want a rifle that goes bang every time regardless of conditions then i would choose the piston. </div></div>

Here is the "hot bolt theory" with DI debunked:

http://www.defensereview.com/the-big-m4-...-m4-unreliable/
 
#30
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Falar</div><div class="ubbcode-body">

Here is the "hot bolt theory" with DI debunked:

http://www.defensereview.com/the-big-m4-...-m4-unreliable/

</div></div>



Read the article and really nothing is debunked. First, the test is worthless when you change the recoil spring and the buffer to a heavier one to compensate for the slowing of the bolt due to increased friction. He states in the article himself that the change of spring and buffer was significant.

That by itself means that "modifications" were needed to make it run that much. Also, the number "2400" rounds are meaningless to me cause they were done in different sessions allowing the rifle to cool. He states that he shot 330 rounds in 25minutes. That is one shot every 4.5 seconds.

That is not even close to combat shooting. 4.5 seconds is a lot of cooling time between shots. Even firing one shot every second which is still pretty slow for combat conditions should have only taken less than 6 minutes. So again that article does not prove anything. Why dont you go and do 4 mag dumps and pull the bolt out and hold it in your hands and video tape it for us
smile.gif
 
#31
Re: PISTON AR10 CONVERSION

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: alpha6164</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Falar</div><div class="ubbcode-body">

Here is the "hot bolt theory" with DI debunked:

http://www.defensereview.com/the-big-m4-...-m4-unreliable/

</div></div>


Been done, with the 416/417 anyhow



Read the article and really nothing is debunked. First, the test is worthless when you change the recoil spring and the buffer to a heavier one to compensate for the slowing of the bolt due to increased friction. He states in the article himself that the change of spring and buffer was significant.

That by itself means that "modifications" were needed to make it run that much. Also, the number "2400" rounds are meaningless to me cause they were done in different sessions allowing the rifle to cool. He states that he shot 330 rounds in 25minutes. That is one shot every 4.5 seconds.

That is not even close to combat shooting. 4.5 seconds is a lot of cooling time between shots. Even firing one shot every second which is still pretty slow for combat conditions should have only taken less than 6 minutes. So again that article does not prove anything. Why dont you go and do 4 mag dumps and pull the bolt out and hold it in your hands and video tape it for us
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#32
Re: PISTON AR10 CONVERSION

Until any of these "testers" start using thermography for their tests, everything is speculation and much of it borders on snake oil.

This M1A had 15 slow fire rounds through it and these images likely tell more of a story than if I had fired 200 rapid fire rounds. Most notably, where the majority of the heat is generated, how it travels throughout the weapon, and how long it takes to get there.

A piston bolt doesn't need a gas system to get it hot. It will get far hotter than anyone can hold in their hand and the only difference is that it will take longer to get it there. Depending on barrel length (which is the single biggest factor) the gas doesn't get significantly hotter based on the number of rounds fired.

The significance of these images should be clear...that most of the heat is generated by the big white flame in approximately the center of the barrel. Absolutely <span style="text-decoration: underline">nothing</span> will stop that heat from transferring throughout the weapon, whether DI or piston if fired long enough.

It's one of the reasons I'll avoid piston guns for now (except for my trusty old battle axe)...they test them largely through trial and error in the age of thermography.

269-ir-4506.jpg


268-ir-4503.jpg
 
#33
Re: PISTON AR10 CONVERSION

Here is a transcript over an interview with John Noveske. The beginning goes over his opinion of the DI Vs piston. Transcript

Also in regards to the "dust test" by Army Times i wonder if the subjected M4 was just pulled from the shelf, rather than perhaps HKs or FNs carefully selected rifles that may be looser more reliable but less accurate. Just a thought.
 
#34
Re: PISTON AR10 CONVERSION

Nobody is forcing anyone to get a piston system. However, they are selling very well in the current market. Take a look at how many POF or LWRC posts there are on this forum.

Having the versatility of mission specific weapons makes it so you can tailor what you need to the environment and conditions you may encounter. Is there a magic "one size fits all" gun? No, but that is why I own more than one gun!

I also am amused when Noveske and Colt owners start arguing how their guns are more "spec" than everyone else's. My slingshot is more "match" than yours.
 
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