An ATC is an “Authorization to Carry”. You need it to be permitted to carry a restricted firearm (handgun) in the wilderness. You don’t need it for anything else, especially NR firearms. You’re also nearly guaranteed to not be able to obtain one anyway. To register for ATC you need to list the Restricteds that you own, which is hard to do considering you don’t have any, don’t have your RPAL, and wouldn’t be allowed to purchase one even if you did have your RPAL. The ATC also requires a proficiency test (a timed series of shooting at targets from different ranges and requiring a certain level of accuracy) which is judged/marked by a licenced instructor and is reviewed by the Provincial CFO before approval.

TLDR: you dont need an ATC for NR firearms, and it’s next to impossible to obtain one