Nice upper.

What I have found for canned use is:
Noveske Switchblock
Noveske N4 10.5
Lt stealth upper
DB youngs bcg
Pri gasbuster
Hk 416 buffer and spring.
Been shooting this my last couple of outings suppressed only, because that is the point of this upper. Fully cycles and locks back even with green/white box remington ammo. Althought I have not tried the upper on the unsupressed settings with the can removed I dont even want to. I think for unsupressed use I would go with another setup just becuse of poi changes with removeing the can which is the old M4 2000 18 tooth setup.

But I am realing liking this setup for canned use as it is as smooth as a slicked up 10/22 recoil wise.