I am in the process of adding rafter ties in my garage. I just got a small compressor and switched from hand to my placement nailer. Unfortunatly They have to be attached over the rectangular mending plates holding the trusses together right above the top plate. By hand I had to predrill the plate using the tie down holes as a guide. No way to drive a nail through the metal. I did the same for the gun then went and tried without. It shoots the 1.5" nails right through the plate. No drilling needed! Most of them need to be seated by a big hammer into the 50 year told dry, old growth doug fir 2x4's.
Bill D
I am wearing a loggers helmet with face shield just in case. Also prevents shingle nails from tearing up my scalp.