Could a heavyweight KO a welterweight with a jab?srs

[King_]

Absolutely. Without a doubt. Anybody who says no is a certified idiot, IMO.

There's weight classes for a reason.

[cameronpaul]

maybe even a middleweight

[Interloper]

Being that a heavyweight jab is like a cruiserweight right cross, the answer is yes. A jab from most any heavyweight could knock out a welter. It wouldn't, most of the time, but definitely could.