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Discussion in 'AR-15 Discussion' started by Abc1911, Oct 27, 2012.
What do you have? What do you prefer?
Whats the diffrence between gas and piston
Piston connects the bolt carrier to a piston that extends into the gas tube. When the gas goes through the tube it acts directly on the piston and pushes the bolt carrier back into the receiver.
With DI the gas enters the bolt carrier and spreads the carrier and bolt apart. As it spreads the carrier is pushed backwards from that force alone, kind of like a swimmer pushing off the end of a pool. Recoil is much lighter this way. Less stress on your rifle as well. Only problem is fouling inside the carrier and some seepage into the receiver. It's no big deal. The upper receiver comes right apart and you can remove your bolt and soak it in kerosene or whatever you're using to remove the carbon buildup.
Piston is seen as more reliable akin to the AK47. The AR adaption of the piston is not the same, though. The AK47 has loose tolerances throughout, while the AR is more of a modular precision instrument.
If you want to eliminate the recoil buffer tube, you'll require a piston setup that relocates the recoil spring to the piston. This is the only benefit I see from it, and it doesn't quite justify the price for me.
I'd prefer the lighter recoil of the DI. If you want a piston rifle, you can practically get two 5.57mm AK's for the cost of one mid grade factory AR.
I prefer the simplicity of the original DI system. Keep the rifle clean and it'll run fine.
He said it best. DI system , cleaning it after a range trip. And it will eat anything you feed it.
I would argue that the ak47 is more like direct impingement than a piston. The ak doesnt have a seperate piston in a block up front that smacks an oprod. The whole thing moves rearward. The ak just has a very long gas key that extends up towards the gas block while the ar15 uses a tube to get the gas to the gas key on the bolt carrier.
I think its incorrect to say the ak47 is a gas piston gun as thereis no seperate piston transfering gas energy to an oprod.
Excellent point, Jon. I'd never looked at it from that angle.
Honestly it depends upon what the individual wants. In all my years with the AR-15 Rifle System and Direct Gas Impingement system I have never had any problems. This is due to the fact that all the weapons I have had has the correct Gas Port Hole and Buffer installed. So when it comes to reliability there are no difference in reliability which is the main factor. One thing I would suggest is that one needs to always cleaning the bore of the rifle with the Front Sight in the up wright position not in the down position allowing solvent to drain into the gas port hole. You have a hydraulic action when pushing the cleaning patch and solvent as well as gravity which could cause a problem. The Gas Piston System must also have the correct Gas Port Hole dimension. There are issues where people talk about the Gas Piston System keeping the Receiver cleaner and there is some truth to that. But who allows their weapon to get dirty to the point that either system stops working. Not most of us for sure. The only other issue is the AR Gas Piston System are more expensive. One other caution! Never buy a retrofit kit that is not completely designed to be a Piston System.
The Cam pin will eat out aluminum on the interior of the Receiver. The Bolt Carrier will tilt as it is forced back and begin to damage the Receiver, Extension Tube and Buffer Retainer area of the weapon. So for advise if you choose a Gas Piston System be sure it was designed from the ground up to be a Piston System. The one I prefer over the others is the Adams Arms Upper Receiver.
There are others out there that are OK!
I prefer direct gas impingment. As has been said it's simple and it works fine in a standard AR. Now if you want a short barrel or suppressed AR then there can be advantages to piston. 14" and up, not so much unless you've got a thing about white gloves.
Di wins by an overwelming numbers. And prolly by another factor of 10,000:1 if you factor leo/miltary procurements.
I have both. Depends on what you use it for as to which is better. If you are firing tens of thousands of rounds a year through the same rifle, a piston might be advantageous. A couple of hundred rounds a month, not so much so. If you are getting your first AR, go with a teir 1 DI and it will eat whatever ammo you feed it.
I have both types also, and would go to war with either one.
I built mine. A lot of the reliability issues depends on who built it with what parts.
There are probably 2 types of people who beleive that the piston is light years above the DI: those who were in the service, and had negligent armorors and/or leaders who passed the blame off on the user for not getting their gun white glove clean before firing, and those who purchased a DI that was either built improperly, or had defective parts. I have been at the butt end of both scenarios, and I feel the pain. However, replacing a bottom of the barrel DI with a bottom of the barrel piston is just swapping one set of problems for another. There are companies like HK and POF who make the top of the line piston systems which make the concept attractive, and they show their AR type rifles shooting from underwater, after pulling them out of the sand, etc, and there are the bottom feeders like Vulcan/Blackthorne which make guns that you better be wearing ballistic protection if you shoot, whether it be piston or DI. My point is crap is crap, whether it be DI or piston.
Man I have been cleaning AR's for a zillion years. See even us old guys can learn something here. Thanks
Just don't let those idiots from Red Jacket install it!!
I installed an ARES Black Lightning piston kit when they first came out, and haven't had any problems with it. Installed a couple on friends guns too, and no issues. I think Bushmaster bought their piston kits and marketed them under their own name.