:flame:
Whatever you used to calculate is weird. This is what I got:
Magneton having 252 Evs and a Modest Nature gives it 372 Attack Power.
Camerupt with 0 Evs and a Naive nature gives it 167 Defense Points.
Magneton uses Metal Sound the first turn lowers my defense 2 points.
Magneton uses Hidden Power Ice, with a base 70 power, doing neutral damage against a Camerupt (Ice verses Ground/Fire). Magneton is also equiped with a Life-Orb.
372 Atk vs 83 Def & 344 HP (70 Base Power): 292 - 344 (84.88% - 100.00%)
Oh snap, there is a small chance that if you did completely and absolutely max damage that you might get the kill. Shift Camerupt's last 4 evs from it's speed into it's special defense, and the chance becomes comletely 0 (although I still feel that this counter is acceptable as is).
372 Atk vs 84 Def & 344 HP (70 Base Power): 289 - 340 (84.01% - 98.84%)
So, if you really want to be that anal about the uber small chance, Counter:
Camerupt @ Leftovers
Naive/Solid Rock
252hp/252specialattack/4specialdefense
Flamethrower
EarthPower
Stone Edge
Rock Polish
:flame: