AR15's - direct impingement vs gas piston

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campinginaz
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AR15's - direct impingement vs gas piston

#1

Post by campinginaz »

I've been thinking about getting into gas piston more than direct impingement. My opinion is they are the best of both worlds AR15 and AK47. I bought a used PWS AR15 from Tombstone Tactical about 10 years ago and it had an aftermarket buffer which caused it to not cycle well. I called PWS and they sent me a free buffer even though I was willing to pay for one. It runs like a champ now.

I know there are many articles such as https://www.pewpewtactical.com/best-ar- ... sion-kits/

I'd like to know if any of you have gas piston AR's and do you like them more than traditional direct impingement. There are so many brands out there now and I'd love to know more from you guys.


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Re: AR15's - direct impingement vs gas piston

#2

Post by Gatsby »

My 300 BLK upper is piston (Adams Arms). I don't see much benefit to a piston system unless you run it suppressed, which is why I had to convert my upper using the "P" conversion kit. With a can, the upper gets gunked up pretty quickly on a DI system. But I haven't had any problems since I converted it (about 8K ago).
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Re: AR15's - direct impingement vs gas piston

#3

Post by campinginaz »

Gatsby wrote: February 21st, 2023, 3:38 am My 300 BLK upper is piston (Adams Arms). I don't see much benefit to a piston system unless you run it suppressed, which is why I had to convert my upper using the "P" conversion kit. With a can, the upper gets gunked up pretty quickly on a DI system. But I haven't had any problems since I converted it (about 8K ago).
I was looking into the Adams Arms quite a bit yesterday. I don't run suppressed but I can see the benefit if you do. Good to know you like the Adams Arms, they seem to be a lot cheaper than others but still have great reviews.
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Re: AR15's - direct impingement vs gas piston

#4

Post by Suck My Glock »

I've built a few piston rifles, back before everyone had it figured out. There were some good conversion units and some bad ones. The bad ones are no longer made and only the good ones continue to be manufactured. I've run piston conversions by Osprey, Adams Arms, Ares and PWS. The PWS is not a "BAD" system, but it has more mass than the others, so it recoils just a bit more than the others. My current rifle uses the out-of production Ares GXR-35 Black Lightning conversion, which they stopped selling in 2015 to focus on the Shrike and other projects. If it ever has a problem, I'll probably be SOL for replacement parts, but it has troopered on for over 10 years now. The only problem I ever had was that my kit was sold back before folks figured out how to fix "carrier tilt" where the back end of the carrier was hitting the front edge of the buffer tube. Current piston carriers have rounded bulbous dimensions at the rear end to ensure the carrier doesn't catch the buffer tube and chew it up or jam. Another solution, for those like me who had an older carrier with traditional (original) dimensions like that of the DI carrier, was the new buffer tube with a slight extension around and forward of the buffer stop, so that the carrier was never fully forward of the tube, and if it tilted, tilted downward onto the buffer tube and could not jam up. I got one made by POF that they use on their own rifles, and my old Ares piston conversion has never caused me grief since.

There are 2 main reasons I am a convert to pistons over DI;...insensitivity to ammo variances and cleanliness/reliability.

Now if you always have proper ammo and proper lube, neither of these should matter. But as the ammo droughts of the last 20 years have shown us, the ammo supply chain is fragile and you have to be prepared to use whatever crappy ammo you might have access to. How many of you experienced TULA steel cased .223 failing to operate reliably in DI carbine length gas systems? That was the failure of TULA using a powder with a burn rate that was inappropriate for the DI carbine gas port locations. But that same ammo fed into any .223 AK or piston-driven AR cycled just fine. Likewise, while CLP or BreakFree or many other gun oils will keep a DI AR rifle chugging along, plain old WD40 will actually absorb all that carbon and crud like clay and start gumming up the rifle. This is because the DI is puking into itself. But on a piston gun, your selection of lubricants is not so potentially fatal as that. I've run my piston rifle with WD40 for thousands of rounds without a hiccup. I've seen DI guns start to short-stroke due to gumming up with WD40 sludge after only 250 rounds, depending on the propellant of a given loading.

Do piston ARs recoil more than a DI rifle? Negligibly, yes. The difference is minor. We are talking mere 5.56 after all, which doesn't recoil that much to begin with. And on larger calibers in AR10 types, the difference is even less noticeable.
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Re: AR15's - direct impingement vs gas piston

#5

Post by campinginaz »

Suck My Glock wrote: February 21st, 2023, 9:45 am I've built a few piston rifles, back before everyone had it figured out. There were some good conversion units and some bad ones. The bad ones are no longer made and only the good ones continue to be manufactured. I've run piston conversions by Osprey, Adams Arms, Ares and PWS. The PWS is not a "BAD" system, but it has more mass than the others, so it recoils just a bit more than the others. My current rifle uses the out-of production Ares GXR-35 Black Lightning conversion, which they stopped selling in 2015 to focus on the Shrike and other projects. If it ever has a problem, I'll probably be SOL for replacement parts, but it has troopered on for over 10 years now. The only problem I ever had was that my kit was sold back before folks figured out how to fix "carrier tilt" where the back end of the carrier was hitting the front edge of the buffer tube. Current piston carriers have rounded bulbous dimensions at the rear end to ensure the carrier doesn't catch the buffer tube and chew it up or jam. Another solution, for those like me who had an older carrier with traditional (original) dimensions like that of the DI carrier, was the new buffer tube with a slight extension around and forward of the buffer stop, so that the carrier was never fully forward of the tube, and if it tilted, tilted downward onto the buffer tube and could not jam up. I got one made by POF that they use on their own rifles, and my old Ares piston conversion has never caused me grief since.

There are 2 main reasons I am a convert to pistons over DI;...insensitivity to ammo variances and cleanliness/reliability.

Now if you always have proper ammo and proper lube, neither of these should matter. But as the ammo droughts of the last 20 years have shown us, the ammo supply chain is fragile and you have to be prepared to use whatever crappy ammo you might have access to. How many of you experienced TULA steel cased .223 failing to operate reliably in DI carbine length gas systems? That was the failure of TULA using a powder with a burn rate that was inappropriate for the DI carbine gas port locations. But that same ammo fed into any .223 AK or piston-driven AR cycled just fine. Likewise, while CLP or BreakFree or many other gun oils will keep a DI AR rifle chugging along, plain old WD40 will actually absorb all that carbon and crud like clay and start gumming up the rifle. This is because the DI is puking into itself. But on a piston gun, your selection of lubricants is not so potentially fatal as that. I've run my piston rifle with WD40 for thousands of rounds without a hiccup. I've seen DI guns start to short-stroke due to gumming up with WD40 sludge after only 250 rounds, depending on the propellant of a given loading.

Do piston ARs recoil more than a DI rifle? Negligibly, yes. The difference is minor. We are talking mere 5.56 after all, which doesn't recoil that much to begin with. And on larger calibers in AR10 types, the difference is even less noticeable.
Thank you for this reply! You are pretty knowledgeable in this subject and I really appreciate you taking the time to post this information. I've never been one to shoot steel ammo because of the issues it can cause with jamming etc. I didn't know that the piston systems eat it up just fine. This means your piston AR is better if you have to use whatever ammo you can find and you can shoot cheaper steel stuff too.

I didn't notice increase recoil in my PWS, like you said it's minimal. I might have to take it out with a DI at the same time and compare to see if I can tell a difference.

How do you like the Adams Arms? Did you do their conversion kit or just buy a complete upper?
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Re: AR15's - direct impingement vs gas piston

#6

Post by Suck My Glock »

The other piston conversions I built were for friends. And while I got to shoot them and experience them, I never put as much ammo downrange with those as I have with my own rifles.

While I am happy with my Ares system, if it ever breaks or if I build another for myself, I'll go with the Adams Arms system. It has more settings and is more adjustable - all parts (except the spring) are nitrided for corrosion resistance - and while it is unlikely anything on it will break, AA is now established enough to bank on them having replacement parts in the foreseeable future, as well as having a valuable reputation to protect by extending customer service. While I am happy with my Ares system, it has none of that.

One of the reasons I do not yet own a .300blk is that I have heard for years that (unlike the .223/5.56 rifles) the variations between subsonic and supersonic loadings in that caliber are a headache in pistol length barrels using pistons, and that DI works best. Although I also hear that it seems CMMG's JAKL pistol upper (which is piston-driven) has finally conquered that voodoo.
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Re: AR15's - direct impingement vs gas piston

#7

Post by campinginaz »

Suck My Glock wrote: February 21st, 2023, 10:19 am The other piston conversions I built were for friends. And while I got to shoot them and experience them, I never put as much ammo downrange with those as I have with my own rifles.

While I am happy with my Ares system, if it ever breaks or if I build another for myself, I'll go with the Adams Arms system. It has more settings and is more adjustable - all parts (except the spring) are nitrided for corrosion resistance - and while it is unlikely anything on it will break, AA is now established enough to bank on them having replacement parts in the foreseeable future, as well as having a valuable reputation to protect by extending customer service. While I am happy with my Ares system, it has none of that.

One of the reasons I do not yet own a .300blk is that I have heard for years that (unlike the .223/5.56 rifles) the variations between subsonic and supersonic loadings in that caliber are a headache in pistol length barrels using pistons, and that DI works best. Although I also hear that it seems CMMG's JAKL pistol upper (which is piston-driven) has finally conquered that voodoo.
I might just have to order an Adams Arms upper! They also have replacement parts on their website so it can't hurt to buy them just in case they do break and you cannot get parts. Thank you again!
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Re: AR15's - direct impingement vs gas piston

#8

Post by mock0013 »

As has already been said pistons run cleaner with a suppressor, but pistons also weigh more and the weight is further forward and that might be an issue for some as the rifle gets longer.
typically expect up to a half pound more.
I'm lazy and don't like to clean so pistons are my friend.
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Re: AR15's - direct impingement vs gas piston

#9

Post by rockbronco »

I have both, My piston upper is a little odd being a pof freedom(I believe it was called that) 16" mid length. Unlike most of their stuff it was a very bare bones setup. forged not billet upper. regular ol Magpul MOE handguard and not a rail etc. The piston system was more or less the same as their flagship stuff so it was a more affordable option at the time but is no longer made if Im not mistaken so if it did every have an issue Im not sure on the parts situation. Ive shot it quite a bit and its does eat everything and stays way cleaner then my DI but IMO thats the biggest advantage.
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Re: AR15's - direct impingement vs gas piston

#10

Post by xerts1191 »

I did the Adams Arms upper a few years ago, my only complaint is a touch of added weight to the rifle. Love the ease of cleaning after 4-5 range tripshttps://www.youtube.com/watch?v=Eil0uxluybo
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Re: AR15's - direct impingement vs gas piston

#11

Post by campinginaz »

xerts1191 wrote: February 21st, 2023, 6:33 pm I did the Adams Arms upper a few years ago, my only complaint is a touch of added weight to the rifle. Love the ease of cleaning after 4-5 range tripshttps://www.youtube.com/watch?v=Eil0uxluybo
Great video thank you for posting. I just order this today. Figured it's worth a try and so much cheaper than my PWS lol.

https://adamsarms.net/product/16-mid-base-upper/
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Re: AR15's - direct impingement vs gas piston

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Post by xerts1191 »

You won’t be disappointed, Adams has done the homework on their products, and always were willing to answer all my stupid questions.
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Re: AR15's - direct impingement vs gas piston

#13

Post by campinginaz »

xerts1191 wrote: February 21st, 2023, 7:52 pm You won’t be disappointed, Adams has done the homework on their products, and always were willing to answer all my stupid questions.
This is great to hear! If I can ask which one do you have?
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Re: AR15's - direct impingement vs gas piston

#14

Post by xerts1191 »

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Re: AR15's - direct impingement vs gas piston

#15

Post by campinginaz »

Nice! Same one I ordered. Heck I might even buy a few boxes of steel cased ammo to see how it runs.
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