DOUGHBOY RACING
New member
Saw these Piston kits and was wondering if the hype is true about the heat and dirty issues they are having in Iraq are true
AR15 Is One With A Gas Piston Cooler, Cleaner,Or not Needed
- Thread starter DOUGHBOY RACING
- Start date
I think it's only beneficial if you are shooting with a suppressor.
"DI or DIE!"
http://www.ar15.com/forums/topic.html?b=3&f=126&t=446047
"DI or DIE!"
http://www.ar15.com/forums/topic.html?b=3&f=126&t=446047
azredhawk44
Moderator
I am not serving, but I have been testing my AR for the last 8 months without cleaning it.
I predominantly shoot either .22LR or .308 through my M14, but I've put about 600 rounds through my AR-15 in that time frame.
Never even added oil or cracked the upper off the lower. Warm it up with 50-100 rounds, some done fairly rapidly and some done slowfire, let the new grit mix in with the old grit and old oil.
No failures at all.
I've predominantly shot handloads using a stick powder (IMR4895) which tends to burn cleaner than the military specified ball double-base powder.
About 200 rounds were Prvi Partizan ammo though, and I have no idea what powder they used.
I finally decided to clean it since I'm installing a free-floated handguard. The BCG was absolutely filthy, but it still worked. The barrel and chamber were just lightly coated with powder-soot. They cleaned right up with no effort at all.
Not scientific and merely anecdotal... but it has convinced me that the AR is not quite so fragile a system as some critics make it out to be.
I predominantly shoot either .22LR or .308 through my M14, but I've put about 600 rounds through my AR-15 in that time frame.
Never even added oil or cracked the upper off the lower. Warm it up with 50-100 rounds, some done fairly rapidly and some done slowfire, let the new grit mix in with the old grit and old oil.
No failures at all.
I've predominantly shot handloads using a stick powder (IMR4895) which tends to burn cleaner than the military specified ball double-base powder.
About 200 rounds were Prvi Partizan ammo though, and I have no idea what powder they used.
I finally decided to clean it since I'm installing a free-floated handguard. The BCG was absolutely filthy, but it still worked. The barrel and chamber were just lightly coated with powder-soot. They cleaned right up with no effort at all.
Not scientific and merely anecdotal... but it has convinced me that the AR is not quite so fragile a system as some critics make it out to be.
Technosavant
New member
A piston introduces certain other potential problems (carrier tilt and buffer tube wear). Not deal-killers, but it doesn't take a rifle that's nothing but trouble and turn it into nothing but wine and roses.
Personally, I don't see the point of a piston system on an AR unless you're going to suppress it, and even then I don't know if it's all that huge a help. I guess I'll find this out myself in a few months when the paperwork comes through, but I'd still really only expect it to be a real problem if you're firing hundreds of suppressed rounds at a time. Even then, it only takes a few minutes to break down the BCG and clean it out.
Personally, I don't see the point of a piston system on an AR unless you're going to suppress it, and even then I don't know if it's all that huge a help. I guess I'll find this out myself in a few months when the paperwork comes through, but I'd still really only expect it to be a real problem if you're firing hundreds of suppressed rounds at a time. Even then, it only takes a few minutes to break down the BCG and clean it out.
NSO_w/_SIG
New member
I'll stick with DI in the AR platform for now thanks.
Bartholomew Roberts
Moderator
Well, what hype have you heard?
1. Does a gas piston AR run cooler than a direct-impingement AR?
First, it depends on what gas piston we are talking about. There are currently a lot of different designs out there and they are not all equal. Some of them are worse than the DI systems they are trying to replace.
Second, it depends on what part of the AR you measure. The bolt can be cooler on a piston AR (and the handguards/gas block will be hotter); but I haven't yet seen any evidence that it makes a difference. Some have claimed that running the bolt cooler improves bolt life and cam pin life; but it seems to me that more modern manufacturing techniques, proprietary bolt designs, and different loading has more to do with differences in bolt life than the temperature. As evidence of this, DI AR15s like the Knights SR15 that use a proprietary improved bolt and barrel extension seem to last longer as well.
2. Does a gas piston AR have a cleaner upper receiver than a DI AR?
Absolutely. The less clear question is "Does it make any functional difference?". I believe Pat Rogers just had a Bravo Company Midlength (DI AR) go 28,905 rounds in training classes with no cleaning at all. It did require some parts replacement as parts wore out; but all they did other than that is add more lube periodically.
Gas piston ARs have advantages over DI ARs in the following areas:
1. Less time to use after being submerged in water - the gas piston has no gas tube to drain so it can be brought into action a few seconds faster.
2. Short barrels (<12.5") with occasional suppressor use. DI gets more sensitive as barrel lengths get shorter. On something like a 10.5" barrel, you have to open up the gas port to get enough gas before the bullet exits the barrel and pressure drops off. However, if you tune that 10.5" to where it is running reliably and put a suppressor on it, you've just added 6" of dwell time and increased backpressure and your rifle is now overgassed. If you tune it to the suppressor, then it won't run at all without the suppressor. Pistons aren't immune to shorter barrel issues; but they are less susceptible to it.
3. Short barrels with major temperature swings (i.e. full auto) - for pretty much the same reasons as above. As things get hotter, temps can get outside the narrow window the 10.5 runs in.
If you are supressing a non-SBR, then it doesn't help much. The suppressor still creates a lot of backpressure and you get carbon in the upper receiver about like an unsuppressed DI. You also still get the occasional gas in the face because most of it is coming via the ejection port/chamber and not the gas tube.
The adjustable gas pistons can be nice to help function with the suppressor; but Noveske and MGI both make adjustable gas for DI systems as well.
1. Does a gas piston AR run cooler than a direct-impingement AR?
First, it depends on what gas piston we are talking about. There are currently a lot of different designs out there and they are not all equal. Some of them are worse than the DI systems they are trying to replace.
Second, it depends on what part of the AR you measure. The bolt can be cooler on a piston AR (and the handguards/gas block will be hotter); but I haven't yet seen any evidence that it makes a difference. Some have claimed that running the bolt cooler improves bolt life and cam pin life; but it seems to me that more modern manufacturing techniques, proprietary bolt designs, and different loading has more to do with differences in bolt life than the temperature. As evidence of this, DI AR15s like the Knights SR15 that use a proprietary improved bolt and barrel extension seem to last longer as well.
2. Does a gas piston AR have a cleaner upper receiver than a DI AR?
Absolutely. The less clear question is "Does it make any functional difference?". I believe Pat Rogers just had a Bravo Company Midlength (DI AR) go 28,905 rounds in training classes with no cleaning at all. It did require some parts replacement as parts wore out; but all they did other than that is add more lube periodically.
Gas piston ARs have advantages over DI ARs in the following areas:
1. Less time to use after being submerged in water - the gas piston has no gas tube to drain so it can be brought into action a few seconds faster.
2. Short barrels (<12.5") with occasional suppressor use. DI gets more sensitive as barrel lengths get shorter. On something like a 10.5" barrel, you have to open up the gas port to get enough gas before the bullet exits the barrel and pressure drops off. However, if you tune that 10.5" to where it is running reliably and put a suppressor on it, you've just added 6" of dwell time and increased backpressure and your rifle is now overgassed. If you tune it to the suppressor, then it won't run at all without the suppressor. Pistons aren't immune to shorter barrel issues; but they are less susceptible to it.
3. Short barrels with major temperature swings (i.e. full auto) - for pretty much the same reasons as above. As things get hotter, temps can get outside the narrow window the 10.5 runs in.
If you are supressing a non-SBR, then it doesn't help much. The suppressor still creates a lot of backpressure and you get carbon in the upper receiver about like an unsuppressed DI. You also still get the occasional gas in the face because most of it is coming via the ejection port/chamber and not the gas tube.
The adjustable gas pistons can be nice to help function with the suppressor; but Noveske and MGI both make adjustable gas for DI systems as well.
I'd say it's not needed. But by reducing the amount of heat flowing back in to the receiver, you theoretically gain more reliability as it prevents heat-wear. You also reduce the need to lube the BCG every couple hundred rounds.
That aside, my DI AR never failed me, and for the most part, DI ARs are already plenty reliable.
That aside, my DI AR never failed me, and for the most part, DI ARs are already plenty reliable.
Piston AR's are a marketing exercise. For some, any reason that sounds good will do to buy another toy. Especially when the get to show it off at the range.
The only piston rifle I would consider are POF and Ruger. I wouldn't expect to gain anything other than bragging rights as an improvement. Parts availability will be non-existent. Obtaining a spare bolt carrier group won't be cheap, as they are single source only. And not even compatible to each other.
Unless the military buys into a piston platform in ten years, there is no advantage for anyone. It's like buying a BMW or Jaguar - nice cars, no logisitic support at the three major parts chains. You usually can't even get a starter or alternator off the shelf, you have to order it.
Some people want special, but don't want what goes with it.
The only piston rifle I would consider are POF and Ruger. I wouldn't expect to gain anything other than bragging rights as an improvement. Parts availability will be non-existent. Obtaining a spare bolt carrier group won't be cheap, as they are single source only. And not even compatible to each other.
Unless the military buys into a piston platform in ten years, there is no advantage for anyone. It's like buying a BMW or Jaguar - nice cars, no logisitic support at the three major parts chains. You usually can't even get a starter or alternator off the shelf, you have to order it.
Some people want special, but don't want what goes with it.
Technosavant
New member
Thanks for the heads-up. I've seen that some suppressed AR guys swear by the PRI Gasbuster charging handle, so I've probably got one of those in my future.
Bartholomew Roberts
Moderator
I've got a PRI Gasbuster myself but I would recommend the Bravo Company Gunfighter charging handles instead. They are better built than the PRI, half the cost, and as far as I can tell (subjective) just as effective at blocking gas. Both the PRI and Gunfighter will still allow occasional gas through though unless you do the RTV sealant mod to them - and even then you'll still occasionally get a faceful from the ejection port blown in your face. Just the price of quietness I guess
Technosavant
New member
Awesome, thanks.
I don't worry about gas out the ejection port- I'm a righty, not a lefty. That's a problem for whomever might be to my right, not me.
I was looking at the BCM Gunfighter handles (the upper in question is a BCM one anyway), and I know they make awesome stuff. I was wondering if anybody had anything similar to the PRI, since $90 is REALLY steep for just a charging handle with a tall shelf.
RockyMtnTactical
New member
Piston AR15's are hype.
DOUGHBOY RACING
New member
Thanks guys I will just get a standard model
Edward429451
Moderator
On Weaponology today they said HK cured the problem of heat and dirt and demonstrated it by taking off the handguards of a M4 and a 416 and shot a mag then bare handed the gas tube of the 416 and lit a match on the M4's and noted that the BCG could be held in ones hand also.
So there you have it. The HK is the winner and obviously worth the extra 4000 dollars...
I'll keep my cheap ol Bushy...
So there you have it. The HK is the winner and obviously worth the extra 4000 dollars...
I'll keep my cheap ol Bushy...
Technosavant
New member
There's a lot to be said for this. The only times I've read that the differences REALLY become apparent are when you're dumping hundreds upon hundreds of rounds in a real hurry.
I don't know about most people, but I can't imagine getting into a furball like that- anything that apocalyptic has more immediate concerns anyway.
Not meaning to hijack the OP's thread, but I too, am on the fence between DI and GP. I'm not going suppressed, I'm not going SBR, and I'm definitely not going to be going full auto. The one and only reason I'm interested in a GP platform is CLEANLINESS. I hate cleaning an AR and the GP makes that job a lot easier.
Problem is, they're expensive. But.....I recently discovered that CMMG is offering a complete GP upper for about $680 with a few nice features. Now I'm really interested! Dammit I had just about made up my mind too! Now I'm back to playing tug-o-war with myself!
http://cmmginc.secure-mall.com/shop/index.php?cat=96&
Problem is, they're expensive. But.....I recently discovered that CMMG is offering a complete GP upper for about $680 with a few nice features. Now I'm really interested! Dammit I had just about made up my mind too! Now I'm back to playing tug-o-war with myself!
http://cmmginc.secure-mall.com/shop/index.php?cat=96&
Bartholomew Roberts
Moderator
If you just hate cleaning it; but don't mind the carbon then just add lube periodically to a good DI rifle and it will run fine, though it will get pretty filthy.
If the carbon bothers you, then you'll have to decide how bad you want the easier cleaning. Although typically, I don't spend more than 10-15 minutes on my DI ARs unless I am just doing it for fun.