Hmmm...well...without wanting to say who is right or wrong about anything...M16 (Armalite, or Similar AR15 etc) use propellant gasses to cycle the action in order to re-load and recock the weapon, as well as chamber the next round...this on its own, means the weapon will recoil less than a bolt action weapon of similar size and calibre....as to weight..the lighter the weapon, the more it will recoil and the less accurate it will be....
I have a .22LR rifle that I use for hunting, lightweight, semi target barrel on it...accurate...but not as accurate as my .22LR Match Rifle...this one weighs 14lb (the other weighs about 7lb) it has a heavy bull barrel and loads of wood on it...but it wil shoot very tight groups and good ranges...and its single shot bolt action...
However (regardless of the fact that .22LR has little recoil anyway), the hunting rifle is Semi Auto, so recoils less than it would if it were a bolt action, lightweight rifle...yet again tho...the fact that that you have a moving mass inside the rifle (on a semi auto or full auto) means that regardless of other variables, they are generally less accurate than their bolt action counterparts, which is why i can shoot tin cans at 800 yards with my .308 target rifle (Military Sniper rifle) but you wouldnt be able to do that with a semi auto version...say the old SLR Nato.