I'm not sure what the ATACR has to do with anything....it SHOULDN'T be any different than any other 34mm tube and 56mm objective.
That said...I'm currently running a 20MOA AADMOUNT (for a 30mm tube) on my AR10 and AR15. For your needs, just order the 34mm model.
You'll be hard pressed to find a one piece mount that is more durable. The design features in this thing are suburb.
If rings are what you want, (and I don't personally like rings unless I'm running a bolt gun. I prefer a 1 piece mount for AR platforms), then the triple lug rings are a fine choice as well.