if your going for mega swampert i recommend 108 hp, 252 att and 148 speed for level 50 (or 104 hp,252 att,152 speed at level 100) just makes sure you outspeed mega aerodactal or mega beedrill under the rain with those spreads.
Also what ginger said for moves but in doubles run protect over rain dance or your going to get caught setting your rain
Also what ginger said for moves but in doubles run protect over rain dance or your going to get caught setting your rain