Mine shot tighter with no rest from that range. Maybe I'm just lucky and got a great one, but I'll do this test this week sometime and post pictures. I have a video of me plinking the heart plate on a steel silhouette no problem at about 20 yards.
Could be sight alignment, even in a rest, you might have the front sight slightly off alignment, maybe I'm wrong, but I don't have any pictures of your test to go off of. It's anecdotal but I shoot tighter groups without a rest than shown here. As others have mentioned, any wiggle room in the rest could also play a role.