I found that by using Winchester Silvertips, I could keep the damage to a minimum. The usual fix for an alloy-framed 1911 is to mill out the feedramp area of the frame and install a steel feedramp insert. I don't know if you want to spend the money, but it would probably work for a PD, too.
Another possibility would be drilling across the frame for a large-diameter steel rod, which is located where the feeding rounds would hit the frame, but preventing the bullets from contacting aluminum. It would have to be precisely located, so it would protect the frame but allow reliable feeding. I've seen some left round, and some, cut to the contour of the surrounding frame ramp.