Why does a heavy rifle not recoil as strongly as a light rifle using the same catridges ?

Why does rifle bullet get heated on striking a target ?

Why does a gun recoil When a bullet is fired ?

Two identical bullets are fired one by a light rifle and another by a heavy rifle with the same force. Which rifle will hurt the shoulder and why?

Two identical bullets are fired one by a light rifle and another by a heavy rifle with the same force. Which rifle will hurt the shoulder and why?