Machamp wins by either using Mach Punch (Or Bullet Punch <_<) and slaughtering Ocelot before he can flinch, or outright catching the bullets and not getting hit.
With four arms that react more quickly than it can think, it can execute many punches at once.
It punches with its four arms at blinding speed. It can launch 1,000 punches in two seconds.
(Those are its Crystal and Diamond version Pokedex entries, which most certainly suggest he can catch a bullet. On top of that, I'd believe that Machamp can tank bullets, but I have no direct info to back it up)
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