I installed a pressure regulator/oiler onto the air line. I had been using the regulator on the compressor which apparently wasn't that accurate. Set hose pressure to 40 PSI. Instead of using the offset rivet shank, I used the curved rivet shank. Also wrapped the bucking bar in several layers of masking tape to protect the ribs.
This time went much much better. The rivets were acceptable although not as uniform as I would like.
