my AR build is
Mag Tactical lower
an Adams Arms upper 16" barrel with a mid length gas system..
I run full magpul furniture with a basic MOE front guard, and magpul vertical .
BCM large handle, ambi safety, fixed 45 degree BIS, DI buffer spring, cheap comp.
I have gen3 and gen4 magpuls and it runs great.

love this gun,
I have had zero ammo issues and tried all sorts of ammo, Tul, Wolf, Brown Bear, surplus military, freedom arms import mostly cheap stuff, but it runs PMC X-tac just fine
I have never taken this to beyond 100m, need to do that. but it shoots nice (6") groups at 100m with a dot, and stays very tight with my scope on it.

I have had one problem with it and it was my fault.. first time cleaning it I put the rod bushing on wrong and mangled my Rod spring..
I have since replaced the spring and bought an extra to add to my AR emergency parts kit.

this build cost me a bit more than a basic AR but I love this gun.