I have been looking into piston driven systems, so I figured this would be the best place to ask questions.
-How does this system work?
-What does this system do better the DI?
Basically can someone just school me on the piston system?
Thanks.
If you are familiar with how a DI system works, the piston is just a little different. In a DI system, you have a gas tube that pulls some of the gas from the barrel down a long tube into the upper receiver. The hot gases and powder residue drive the bolt carrier rearward and allow the spent ammunition casing to be ejected and a fresh one to be loaded. The bolt carrier for a DI rifle has a gas tube receiver on the top of it that fits over the gas tube to create a tight seal. But when the bolt carrier moves backwards a lot of the hot gases that have unburnt powder, primer debris, and fouling can spray all over the inside of your upper receiver and coat your bolt.
What a piston does differently is replace the gas tube with a metal rod. The gas comes off the barrel into a short tube and then drives a long metal rod rearward. The metal piston rod is pushed against a cupped receiver built into the bolt carrier (piston bolt carriers are a little differently shaped on top since there is no gas tube to mate to), and drives the bolt carrier rearward.
The biggest advantage of the piston system is all the hot gases and debris are vented out the front of the rifle form the handguard area and not sprayed into your upper receiver. This is great for moving parts as they don't get coated in debris and unburnt powder residue. Also the bolt in your rifle will remain very cool to the touch with a piston gun, and gets very hot in DI guns.
There are a couple of downsides to pistons. They piston rifles tend to be a little heavier, they can have some carrier tilt if you don't get a piston gun that has a anti-tilt buffer and bolt carrier, and you have to clean the piston (one additional part to clean).
90% of my rifles are piston driven and I love them. I do have a few DI guns and they work great as well. If you clean and maintain your guns, they will work great for you. Piston guns require much less work to clean, and have a softer recoil signature as well.
I would recommend looking at LMT piston AR-15s, LWRC, or even a Stag model 8 (low price and good quality).
Originally Posted By CovertChannels:
If you are familiar with how a DI system works, the piston is just a little different. In a DI system, you have a gas tube that pulls some of the gas from the barrel down a long tube into the upper receiver. The hot gases and powder residue drive the bolt carrier rearward and allow the spent ammunition casing to be ejected and a fresh one to be loaded. The bolt carrier for a DI rifle has a gas tube receiver on the top of it that fits over the gas tube to create a tight seal. But when the bolt carrier moves backwards a lot of the hot gases that have unburnt powder, primer debris, and fouling can spray all over the inside of your upper receiver and coat your bolt.
What a piston does differently is replace the gas tube with a metal rod. The gas comes off the barrel into a short tube and then drives a long metal rod rearward. The metal piston rod is pushed against a cupped receiver built into the bolt carrier (piston bolt carriers are a little differently shaped on top since there is no gas tube to mate to), and drives the bolt carrier rearward.
The biggest advantage of the piston system is all the hot gases and debris are vented out the front of the rifle form the handguard area and not sprayed into your upper receiver. This is great for moving parts as they don't get coated in debris and unburnt powder residue. Also the bolt in your rifle will remain very cool to the touch with a piston gun, and gets very hot in DI guns.
There are a couple of downsides to pistons. They piston rifles tend to be a little heavier, they can have some carrier tilt if you don't get a piston gun that has a anti-tilt buffer and bolt carrier, and you have to clean the piston (one additional part to clean).
90% of my rifles are piston driven and I love them. I do have a few DI guns and they work great as well. If you clean and maintain your guns, they will work great for you. Piston guns require much less work to clean, and have a softer recoil signature as well.
I would recommend looking at LMT piston AR-15s, LWRC, or even a Stag model 8 (low price and good quality).
I would agree with everything in this post, except the red line. Cleaning the piston itself to me is not a real disadvantage, considering it takes 3 seconds as opposed to cleaning your whole BCG, which most piston users probably don't ever do, or only do out of habit.
I also wanted to throw Adams Arms kits in there. They are high quality, with great customer service, and if you don't want to buy a whole new rifle you can get a retro kit to add to one of your current rifles. They also have complete uppers that are top quality (so I've heard, I built mine).
i have not had my stag 8L for too long but I can attest to the ease of cleaning and coolness of the BCG. Please note that the gas block gets very hot after sustained shooting, hotter (IMO) that a DI gun.
Read around and ask many questions. With this forum, you'll make the right decision for your needs.
