View Full Version : Adams Arms AR-15 Retro-fit Piston Driven System
One of the biggest controversies surrounding the AR platform is the Stoner designed gas impingement system. Basically, it is a gas port from the barrel that funnels expanding gas into a gas tube directly to a gas key on the bolt carrier. The expanding gases force rearward movement in the carrier and is bleed into the bolt as well forcing it to unlock the breech. While this keeps the system simple and very light, it also creates a lot of residue inside the mechanics of the upper and lower receiver. Several recent designs by HK, POF-USA, and LWRC have taken the AR platform and turned it into a piston driven system as a departure from the original design. Torture tests have all concluded that you can run these systems at full auto for much longer than the traditional design without the common catastrophic failure of the weakest point... the gas tube.
Today, I got a chance to try out my Spikes M4-gery with a Adams Arms piston retro kit installed. This kit took about 30 minutes to install and basically replaced the bolt carrier gas key, gas tube and gas block with a high quality piston kit. While only putting less than 200 rounds today, the gun ran flawlessly. I was impressed with the reduction of an already mild recoil and most importantly, the complete elimination of any gas from the receiver. The bolt was amazingly clean even if it was only 160+ rounds. The gas block itself did get hot, but the bolt was easily lukewarm at best. I've included some pics of the system. If anyone is interested in looking at the kit, Rich at Guntech has a few in. In the meantime, I'm going to try to take it to a range where the 1 second rule doesn't apply and report back.
I should have taken the opportunity to shoot that one also when you offered today. I like the idea of no gas blowing in your face and the fact the gun runs cleaner and cooler.
Chris
10-12-2008, 05:52 PM
good write up and good looking kit, hope it serves you well into the future
Satan_3pc
10-12-2008, 08:52 PM
Hmm, neat. Yeah my Rock River man... I shot it at an indoor range a couple of weeks ago. Holy shit! Talk about a lot of gas. I could smell it almost overwhelmingly. I mean the place had vent systems and air filters and stuff, but I didnt realize how big the cloud of gas that comes out is until I was indoors.
hey ss1 how much was the kit? would it fit with UTG quad rails?
It was four and some change. Rich originally had 8 kits directly from Adams Arms and they sat around for the entire time the store was getting built. This rifle was on the wall at Guntech and within a few weeks of this write up, they were all sold. Since then, Adams Arms is no longer selling directly to dealers. Now, dealers must use a distributor, so I am not sure where prices are or availability. I know Rich has tried to order more, but there's probably a backorder. We used to sell a whole ton of UTG rails, but I haven't seen one well before the Adams Arms kits had come in. IIRC, they had placed a huge order of rails and then their rep no longer worked there and it turned out the rep never submitted their order. I think they straightened it out at the SHOT show with them, but I still haven't seen any. The AA system does need significant clearance for the piston and rod. So far I can tell you that the Daniel Defense Omega rail works and the Troy MRF rails do not.
Secpro
04-02-2009, 08:53 AM
I have a UTG rail myself and to by a whole new rail system to fit the piston isn't really on my list of things to do. The piston kit seems to be a good if not great idea but in the end all it does is save a little time and allow you to put a few more rounds down range. Doesn't seem to be of a necessity to me. In some ways I love cleaning my guns after a range day. Beer a grill and a set up cleaning doesn't seem all that bad as a pose to an additional $4-500 bucks.
liquidsniper
04-02-2009, 10:43 AM
I have given thought to installing a piston system in my AR but have avoided doing so for a couple of reasons.
The first reason is carrier tilt. The piston places torque on the gas key causing the back of the carrier to tilt down causing scrapes along the buffer tube and shearing gas keys. The AR platform was designed as a free floating bolt carrier. Now some companies have been able to remedy this such as LWRC by installing carrier guide rails and going to solid one piece carriers. However, I still think that the AR was designed as a gas operated gun and I see many operating just fine. I have seen just as many problems with piston guns. I can understand the cleaner arguement as the DI system can be very dirty, especially with suppressed applications. However, I am very particular about cleaning my rifles. Anyways, I am no expert nor claim to be one just giving my view about the other side of pistons on the AR-15
Secpro
04-02-2009, 02:02 PM
I have given thought to installing a piston system in my AR but have avoided doing so for a couple of reasons.
The first reason is carrier tilt. The piston places torque on the gas key causing the back of the carrier to tilt down causing scrapes along the buffer tube and shearing gas keys. The AR platform was designed as a free floating bolt carrier. Now some companies have been able to remedy this such as LWRC by installing carrier guide rails and going to solid one piece carriers. However, I still think that the AR was designed as a gas operated gun and I see many operating just fine. I have seen just as many problems with piston guns. I can understand the cleaner arguement as the DI system can be very dirty, especially with suppressed applications. However, I am very particular about cleaning my rifles. Anyways, I am no expert nor claim to be one just giving my view about the other side of pistons on the AR-15
:+1: there bud!
if they were in the $250.00 range and good quality.. Id get one