Hi All,
I recently purchased a rifle length gas piston system from Adams Arms for my 20" Krieger/CLE barreled rifle. My rifle previously worked flawlessly with a YHM gas block but I wanted to try the AA system as I have ordered a suppressor. Used a known-good Magpul 20-round magazine.
SETUP: 20" Krieger barrel/wylde chamber, DPMS upper & lower, rifle buffer, rifle buffer tube, Tubbs buffer spring, Daniel Defense 12" Lite Rail, standard bolt carrier with their retrofit.
THE GOOD:
1. Adams people are great to work with. Got to talk directly with Jason for tech support.
2. System is very high quality and well designed. Looks simple and robust.
3. I have read nothing but rave reviews on AR15.com....30+ pages of glowing reviews. Many folks have shot thousands upon thousands of rounds without any issues.
4. The system can be put on existing ARs without any modifications. Simply remove the gas block and add their system. (Rail compatibility is an issue but AA has the best compatibility of all the ones I looked at).
5. They quickly refunded my money as promised if I wished to return it, which I did. See below for info.
THE BAD:
1. The Daniel Defense "bolt-up plate" that attaches the rail to the rifle had to be dremeled a little to allow the piston to slide through the gas tube hole without binding. Minor issue but worth noting.
2. With my setup, the system did not work reliably. It worked about 80%. 20% of the time, the spent case would extract, but the bolt would not move far enough to the rear to catch the next round. I tried a variety of things to remedy this problem: removed various springs from the AA system, Moved the gas block forward, backward, side-to-side, tried different types of ammo. I also removed to DD rail to make sure it was not causing any binding issues. Nothing helped. I could tell the gas block was properly centered right over the gas port by the dust print. I talked to AA but did not resolve the problem and sent the system back.
3. Carrier tilt/buffer tube scraping. Yes, there is carrier tilt and a small amount of scratching of the receiver/buffer tube area occurred. Importantly, this only occurred for the first 10 rounds or so and then no further damage was done on subsequent shots. This is a really minor issue as it caused hardly any damage and then ceased to cause any more damage once it was "worn in" so to speak. ANY gas piston retrofit will have carrier tilt because of the mechanics. The only thing that can be done is to use a bolt carrier with a flared rear that fits more tightly and thereby minimizes the tilt. Overall, I think this is an overrated problem...let it wear in and forget about it.
4. Recoil. You definitely notice a slightly sharper recoil impulse, not like the normal "push" a standard AR gives. Not a big deal, but it is noticeable.
OTHER ACTIONS:
There are two things that I did not try. I could have increased the size of the gas port and I believe that may have resolved the problem. However, I did not want to modify a system that has worked flawlessly with a regular gas system. I also could have replaced the Tubbs buffer spring with a standard spring. This may have worked and I only thought to try this after sending the system back...doh.
SUMMARY:
I believe the Adams Arms piston retrofit is best suited for mid-length and carbine-length gas systems where the port pressures are higher and the need for a piston system is greater. I still think AA makes one of the best piston retrofits out there and I probably could have gotten it to work if I enlarged my gas port. Instead of doing this, I have decided to get an adjustable gas block (JP) and that should allow me to compensate for a suppressor nicely.
One interesting side-benefit of this exercise: my appreciation for the simplicity and reliability of the original rifle length system has grown. IMHO, rifle-length gas systems have no problems that need to be "fixed." An adjustable gas block will allow me to shoot with a suppressor just fine. Not having a moving piston on top of the barrel really does have a bunch of advantages. The downside is you get to scrape carbon off your bolt from time to time.
I recently purchased a rifle length gas piston system from Adams Arms for my 20" Krieger/CLE barreled rifle. My rifle previously worked flawlessly with a YHM gas block but I wanted to try the AA system as I have ordered a suppressor. Used a known-good Magpul 20-round magazine.
SETUP: 20" Krieger barrel/wylde chamber, DPMS upper & lower, rifle buffer, rifle buffer tube, Tubbs buffer spring, Daniel Defense 12" Lite Rail, standard bolt carrier with their retrofit.
THE GOOD:
1. Adams people are great to work with. Got to talk directly with Jason for tech support.
2. System is very high quality and well designed. Looks simple and robust.
3. I have read nothing but rave reviews on AR15.com....30+ pages of glowing reviews. Many folks have shot thousands upon thousands of rounds without any issues.
4. The system can be put on existing ARs without any modifications. Simply remove the gas block and add their system. (Rail compatibility is an issue but AA has the best compatibility of all the ones I looked at).
5. They quickly refunded my money as promised if I wished to return it, which I did. See below for info.
THE BAD:
1. The Daniel Defense "bolt-up plate" that attaches the rail to the rifle had to be dremeled a little to allow the piston to slide through the gas tube hole without binding. Minor issue but worth noting.
2. With my setup, the system did not work reliably. It worked about 80%. 20% of the time, the spent case would extract, but the bolt would not move far enough to the rear to catch the next round. I tried a variety of things to remedy this problem: removed various springs from the AA system, Moved the gas block forward, backward, side-to-side, tried different types of ammo. I also removed to DD rail to make sure it was not causing any binding issues. Nothing helped. I could tell the gas block was properly centered right over the gas port by the dust print. I talked to AA but did not resolve the problem and sent the system back.
3. Carrier tilt/buffer tube scraping. Yes, there is carrier tilt and a small amount of scratching of the receiver/buffer tube area occurred. Importantly, this only occurred for the first 10 rounds or so and then no further damage was done on subsequent shots. This is a really minor issue as it caused hardly any damage and then ceased to cause any more damage once it was "worn in" so to speak. ANY gas piston retrofit will have carrier tilt because of the mechanics. The only thing that can be done is to use a bolt carrier with a flared rear that fits more tightly and thereby minimizes the tilt. Overall, I think this is an overrated problem...let it wear in and forget about it.
4. Recoil. You definitely notice a slightly sharper recoil impulse, not like the normal "push" a standard AR gives. Not a big deal, but it is noticeable.
OTHER ACTIONS:
There are two things that I did not try. I could have increased the size of the gas port and I believe that may have resolved the problem. However, I did not want to modify a system that has worked flawlessly with a regular gas system. I also could have replaced the Tubbs buffer spring with a standard spring. This may have worked and I only thought to try this after sending the system back...doh.
SUMMARY:
I believe the Adams Arms piston retrofit is best suited for mid-length and carbine-length gas systems where the port pressures are higher and the need for a piston system is greater. I still think AA makes one of the best piston retrofits out there and I probably could have gotten it to work if I enlarged my gas port. Instead of doing this, I have decided to get an adjustable gas block (JP) and that should allow me to compensate for a suppressor nicely.
One interesting side-benefit of this exercise: my appreciation for the simplicity and reliability of the original rifle length system has grown. IMHO, rifle-length gas systems have no problems that need to be "fixed." An adjustable gas block will allow me to shoot with a suppressor just fine. Not having a moving piston on top of the barrel really does have a bunch of advantages. The downside is you get to scrape carbon off your bolt from time to time.
