ATS or EC Tuner from Kukri Profile to MTU will tune just fine. I currently have an EC Tuner on my new barrel. The old barrel had an ATS. I think the ECTuner is easier to use and tune with as it is tool less. Both of my barrels are 22" & MTU profile.
You see very few barrels in the PRS or NRL22 game below 20" and smaller than Kukri profile.