Just perusing AA's website and noticed that the AA Overwatch now has the option for fluting in addition to the Shilen upgrade.

Shilen's website says they will void the warranty if their barrel is fluted.

???

I'm really interested in this upper, but not sure if I want to risk the fluting on button rifled barrel. Thoughts?

Did AA also reduce the diameter of the barrels or are they the same diameter as previous offering?

They also now feature 9/16" threading...