Old Thread, but I will add my 2 Cents.
In this day and age I would have Brass and Reloading Dies "IN HAND" before doing any build. It can be hard enough to find brass for something that is reasonably common.
I was considered converting my 204 Ruger AR to 6ARC. I am dead in the water on the conversion to 6ARC because of Brass Availability.
I have about decided to go 22 Nosler because I have enough brass on hand from my M48 bolt gun to donate some to the AR Project Gun.
Not saying your choice of cartridges is bad, but make sure that you can feed it before starting the build.