Judah hits hardest with 1 hit. But margo hits pretty hard if he can do a combo. Mosley's power has deminished over the years so he's third, but in his prime he would be at the top
I think Zab has that one punch type power to hurt you, Margarito breaks you down with his relentless work rate, and Shane still has decent puncher. He used to be a harder puncher in his prime I believe though.
Zab
Margarito
Mosley
I don't understand why people are asking ''right now''? Power is power. Judah is the hardest puncher out of the list. Margarito can not get it done with one punch, Judah can. Margarito is a wear you down type of a fighter, similar to Jose Luis Castillio. An insider fighter that smothers you for every minute of every round. Judah was the only fighter to hurt and stop Spinks. Jermain Taylor couldn't even stop a blown up Spinks at middleweight and he connect with a few flush right hands. In my book, Zab is also the only one to drop Mayweather as well. It could have been ruled as a knock down. His power is seriously underrated.
Zab's power is complimented by his hand speed. His opponents don't see his shots comin so they do more damage. Shane's a better puncher than he gets credit for, but he does damage wit accumulated punishment. Tony ain't a 1 punch killer either but he's got more pop than these 2.
It's a close call. Shane doesn't hit like he used to, so he'd be third. Margarito punches consistently harder, but Judah is probably the most dangerous with one punch.
We'll have to ask Cotto in two months.
Zab hasn't had a knockout in three years. Aside from Cintron, Margarito hasn't really stopped anyone of note. Mosley's power carried to 154 where he stopped Vargas back to back 2 years ago. I'll say Mosley.
for 1 punch, it is hard to overlook the effect of Zab's hybrid left hand/uppercut. It can bust guys up.
Margarito is a volume heavy hitter and Shane's power has declined some. All of them can take guys out though and for a single punch, not much separates the three of them.