The factory Colt 901/M7 magazine adapter block conversion kit allows you to install any mil-spec AR15/M4 upper receiver and use mil-spec AR15/M4 magazines with your Colt 901/M7 lower receiver...
Factory Colt Cam Pin for 5.56mm AR15/M4/M5-platform. Currently these are coming with a gray dry lube powdery phosphate finish instead of the older black finish.