1. I built three Grendels using Adam Arms gas piston systems.
2. I liked the fact that they ran cleaner than the D. I. system and were self regulating with the gas system. I had a new 18" barrel that came with an over sized gas port and would not function. The Adam Arms ran perfectly after I installed them.
I had 2 -16" barrels and 1-18" barrel.
3. If you install an Adam Arms piston kit they have excellent instructions on their Web sight or just google it.
4. I noticed the carbine length piston had a lot less recoil than the mid length system , both were 16" barrels.
5. I have since removed all my Grendel gas piston systems and changed back to the D.I. system. They now have great adjustable gas blocks made for the D.I. system like the Syrac or Rifle works SLR. The gas pistons are noticeably more heavy and seem to recoil more for fast follow up shots compared to the D.I. system. I also noticed better and more consistent accuracy with the D.I. system. There are a lot of opinions on the pros and cons of gas pistons vs the D.I. for the AR platform. I personally prefer the D.I. system with an adjustable gas block. I never had any functional problems with the Adam Arms Piston set up but the D.I. system has worked better for what I wanted, mainly less recoil and better accuracy. If you keep the D.I. system well lubed it will run very reliable.
2. I liked the fact that they ran cleaner than the D. I. system and were self regulating with the gas system. I had a new 18" barrel that came with an over sized gas port and would not function. The Adam Arms ran perfectly after I installed them.
I had 2 -16" barrels and 1-18" barrel.
3. If you install an Adam Arms piston kit they have excellent instructions on their Web sight or just google it.
4. I noticed the carbine length piston had a lot less recoil than the mid length system , both were 16" barrels.
5. I have since removed all my Grendel gas piston systems and changed back to the D.I. system. They now have great adjustable gas blocks made for the D.I. system like the Syrac or Rifle works SLR. The gas pistons are noticeably more heavy and seem to recoil more for fast follow up shots compared to the D.I. system. I also noticed better and more consistent accuracy with the D.I. system. There are a lot of opinions on the pros and cons of gas pistons vs the D.I. for the AR platform. I personally prefer the D.I. system with an adjustable gas block. I never had any functional problems with the Adam Arms Piston set up but the D.I. system has worked better for what I wanted, mainly less recoil and better accuracy. If you keep the D.I. system well lubed it will run very reliable.