If you play the first down beat of what would be the beginning of the next iteration of the "loop" when recording, you can just truncate the clip at that point, and then copy-paste as many iterations as you want, one at a time, snapping the Now time to the end of each preceding clip before pasting the next.
It's also fairly straightfoward to snap the timeline to the overall tempo of a clip so that you
can use groove clip looping.