Hi. New to forum. Just purchased a new MP15-22 Sport. Prior to purchase I watched some YT videos re: diasassembly and cleaning. I'd like to thourougly clean this wepon prior to my first range session. However, the instruction manual does not illustrate and disasemply process beyond a partial separation of the lower (by removing the take down pin), and then removing the charging handle and bolt assembly. However, the videos all show the lower being removed entirely by also partially removing the front pivot/hinge pin (sorry, the manual doesn't provide a name for it). That doesn't seem to want to press out. Should I not remove that pin? If I should, how? Thank you.