Not sure how long it will take if you’re in Canada but in USA the process has become quite quick. Fill the application online and send the finger prints. You should get report in pdf in your email within two weeks after FBI receives finger prints. One risk is FBI rejecting fingerprints due to lack of quality. To avoid that go to some place where they take finger prints professionally.
Below are my timelines for getting the US PCC when applied from Canada:
Aug 23rd-
Applied online @fbi site ~25 CAD
Got my fingerprints done with a professional ~45 CAD
Mailed the FBI acknowlegedment + fingerprints via Express CA Post - ~ 30 CAD
Aug 28th - FBI received the mail and within 2 hours shared my PCC via email - enough for PR application
Aug 29th - Received the same copy via Mail