>>19890592252+ Atk Choice Band Technician Breloom Mach Punch vs. 0 HP / 0 Def Mega Kangaskhan: 324-384 (92.3 - 109.4%) -- 50% chance to OHKO
yeah, 50% of the time. and that's with a Band.
252+ Atk Life Orb Technician Breloom Mach Punch vs. 0 HP / 0 Def Mega Kangaskhan: 283-335 (80.6 - 95.4%) -- guaranteed 2HKO
Life Orb can't even OHKO except when Mega-Milf has 0 IVs in both stats:
252+ Atk Life Orb Technician Breloom Mach Punch vs. 0 HP / 0 Def Mega Kangaskhan: 322-382 (100.6 - 119.3%) -- guaranteed OHKO