Custom-built M4 CQB Part 2

I recently upgraded my A&K M4 CQB just to have fun. Though it is just a “semi-upgrade”, I replaced its built-in spring with a PDI 190 and Guarder Spring Guide. There is no need to change the metal bushing on this, for most A&K units that came out are pre-upgraded with metal bushings. Installed Aimpoint Red/Green Scope and a 2,500 round mechanize A&K C Mag.