I did a search and found some info on the 645 ,but not alot. I've been offered a beat up example as a project gun. Are these 645's accurate ,or just "Combat" accurate? How do they hold up under alot of range use? Are parts a problem? Any problems besides the phillips head screw holding the ambi safety? The one I'm looking at is about 80% ,and has adjustable sights. Were adjustable sights an option on the 645 ,or is this an add on? Will it work with my S&W 45XX series mags? Regards 18DAI.