Thought I would knock out the rivets from the skin to the rear spar. Half of these are easy because you can squeeze them. The other half you have to buck and somewhat awkwardly. Despite the fact the I dinged the skin a bit on the left elevator, I didn't find bucking the rivets to be very difficult. I don't know what I was doing wrong today, but I really struggled. Bucking bar was bouncing around, dinged the skin in several places and ended up with about 10 rivets that I had to completely drill out because they were sitting proud. Re-bucked the first few and they still were sitting quite proud of the skin. Very frustrating evening. As if I've lost all riveting skills. I decided to call it a night and walk away before I do any damage. Will deal with those tomorrow.