Some of the magic is in balance as well. Ive found rifle fixed stocks make the gun feel heavier for me as I feel over extended free handing it. Carbine stocks keep the center of gravity closer to the body (for me, YMMV)
My lightest setup is a gun I built using Aero receivers, Ballistic Advantage 16" midlength gas standard barrel, and Daniel Defense 9" 7.62 Lite rail. I was really surprised how light the gun turned out, almost as light as my 300 Blackout rifles.