Is the uppercut the hardest punch in boxing?

No the jab is.

 

You can’t see the uppercut coming and it is seldomly used. Everybody has some type of jab and you can see it coming.

 

It's true that most people with minimal boxing training don't know how to throw or defend an uppercut but you still have to be in the wheelhouse to land it. The jab is a much safer punch and can do a considerable amount of damage by itself.

 

I agree.

 

Nah doe, the one he's running his own head into is the one that works best bruh.

Kinematic chains + Newton's third law = Leverage is key.

I'd go with cross but I think that is more in ubiquity of use than actual physics. Any punch can be the hardest punch because the hardest punch is the one no one saw coming and it is so not because of awareness but rather the physics involved in a rug pull, bait, feint and counter.

Run your face into a wall,it hurts.