I have already got 50 rounds 6mm ARC cases sized and loaded (made some brass out of 6.5 Grendel cases).
Patiently waiting on my barrel...no idea when it will be delivered!?!?!?!?
Going with the longest barrel available, 24" Ballistic Advantage SS barrel. Plan is to just use it for pleasure shooting of steel at longer ranges...the range I visit a couple times a month goes out to 600 yards...but I would like to shoot it further.
40 95gr Nosler BT's and 20 107gr Sierra Match Kings...modest loads with 8208 to fire form the cases and do a little barrel break in.
Please keep us posted on your build with range reports.
I have a Spikes AR lower I built many years ago and it needs an Upper. I am thing about building a 24" 6mm ARC Upper using a Colt Upper. The barrel will be heavy and must be threaded so I can mount my OSS 762 Ti suppressor.