besides most guns, ecspeically shotguns, have a recoil pad and recoil spring that lessen the recoil
Except there is no knockback in the first place. Mythbusters tested that extensively; even if you hit someone squarely in the chest with a full shotgun blast, the force of impact won't even make them stumble, it'll knock them back less than an inch.
also, ur ready for the punch
I repeat; there is no knockback! None! It doesn't matter if you're ready or not.
the enemy is running at u hes not ready to be hit by such a punch
Is this some kind of joke? Physics! It's the most basic elementary physics!
If the person is moving towards you, you'd need an even greater force to cancel out his momentum and propel him backwards!
i have been shoot while having a bullet proof vest on by a 9mm pistol and it feels like being hit by a baseball bat, its crazy
...and the impact from a baseball bat, swung by your average person, is not particularly big. You can get hit squarely in the chest with a round from an AK-47 at point blank range, and you wouldn't be knocked back. The kinetic energy of a rifle or shotgun round is much too small.