I made a minor mistake yesterday by riveting the 5th inboard Main Rib to the spar without the A-1210-R Inbd Nose Rib. Drilled out the 3 pop rivets without problem. I Had trouble riveting the A-1207-R Actuation Bracket to the Spar. It seems that the outboard holes are a little too close to the flange and the rivet heads are not sitting flat. I also could not keep the squeezer head perfectly straight. I squeezed one rivet and it became lopsided and had to drill it out. I reviewed the match-drilling instructions in page 18-04 and I think I followed the directions correctly. Filed the inner corner/angle of the Bracket. I'll try riveting it later because I have to prime the piece again. Deburred the edges of the A-1202B Outbd Flaperon Skin.