If buying a used PD, field strip and check the area where the recoil spring/buffer contacts the frame channnel.
If it's chewed up, it's been shot with a worn-out buffer. Note that the factory finish in this area isn't the prettiest, appears to have been slightly hand-fitted.
The guy in Spain (Star on Gunboards) has no more buffers.
This is the only current source I know of:
http://www.hoosiergunworks.com/images/star_pd_guide_1.jpg$15.00 each
I've only fired a couple magazines through mine, but no problems with hammer bite.
But I don't have a problem with 1911s doing that either.
Nice pistols. I'll probably buy a 2nd PD next time I see one.
PS: All PDs have a vertical frame cut from the slide release hole to the top of the rails. Some people think that is a crack, but it's actually a stress relief cut. You can call it a crack if it will get you a better deal