252+ SpA Volcanion Fire Blast vs. 248 HP / 200 SpD Mega Scizor: 652-772 (190 - 225%) -- guaranteed OHKO

252+ SpA Volcanion Fire Blast vs. 252 HP / 120+ SpD Amoonguss: 374-444 (86.5 - 102.7%) -- 18.8% chance to OHKO

252+ SpA Volcanion Hidden Power Grass vs. 252 HP / 24 SpD Mega Slowbro: 170-200 (43.1 - 50.7%) -- 3.9% chance to 2HKO
(I think we can all assume solar beam OHKOs)

252+ SpA Volcanion Steam Eruption vs. 252 HP / 8 SpD Landorus-T: 470-554 (123 - 145%) -- guaranteed OHKO

2252+ SpA Volcanion Steam Eruption vs. 248 HP / 252+ SpD Clefable: 153-180 (38.9 - 45.8%) -- guaranteed 3HKO after Leftovers recovery

and that's not even specs 0_0