New offer from Alexander Arms and started new build

[montana]

I got an e-mail offer from Alexander Arms and in it is the offering for a 16" 6.5 Grendel light barrel for only $195.00:
http://www.shopalexanderarms.com/Barrels...arrel.html

So I went for it and that means I'm starting a new build based on that. I got also the bolt.
http://www.shopalexanderarms.com/Bolts_a...bly_1.html

Additionally I got from Brownells an Aero Precision upper receiver ($55.00) plus the forward assist. I failed to get the barrel nut in the same shipment.

Now I'm searching for the laser engraved dust cover that says 6.5 Grendel on both sides.

Now to decide on getting an Adams Arms or a Syrac piston system. I have both already in other rifles and both work fine, but I have never exposed them to harsh treatment to test them for reliability. Does anybody have that experience or at least an opinion?

I retrofitted my 18" Grendel with an Adam Arms piston kit because it was over gassed. The piston kit ran flawlessly. When I discovered reliable adjustable gas blocks I have converted back to the DI gas system. The DI system is much lighter, recoils less and is more accurate. The only AR rifle I have with a gas piston is a short barrel 5.56 with a suppressor. If you are ever able to run a AR with a DI gas system next to an AR with a piston system you will understand why I gave up on the gas piston.