Butch,
If it were MY build, and I've built a few patrol rifles in my time, I would go with a LW 14.5" barrel with a JP Enterprises 3-prong Flash Hider pinned and welded, the WOA handguard, nitrided gas tube, nitrided or stainless gas block, pinned if possible, dimpled & Loctite 209, SSA trigger, Magpul ACS Stock, and the other parts you mentioned.
Having climbed in, out, and off of vehicles with even a 16" AR can be clumsy and every inch counts. Add in running, climbing fences, scaling walls or other obstacles
He needs a dead-nuts reliable long gun that should be as precise as possible, understanding that even SWAT snipers rarely shoot beyond 100 yards, so even a 1.5-2 MOA rifle will do anything he will need.
I have NO doubt that Nez will build it to be even more accurate than 1.5MOA.
I'm with Bluedreaux on nixing the WOA rail gas block. Just put the longest hand-guard on it you can and keep the gas block & tube protected. Add a set of Troy Tritium MBUIS and he's ready for anything.
My Patrol rifle(s) still ride with me every day, often strapped on my ATV or resting on the floorboard of my truck as I ramble around the desert, but more often I carry one slung on a VTAC two-point sling They aren't abused, but they aren't coddled either.
Think about an adjustable gas block if he's going to put a can on it. I have done that to mine so I have that option and not over-gas my system. but retain full functionality.
Hope this helps,
Ed
