Here are some completely viable Skarmory sets that you should definitely be using:
Skarmory @ Fightinium Z / Expert Belt
Ability: Weak Armor
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Brave Bird
- Iron Head
- Rock Smash
Swords Dance + Weak Armor Skarmory! With Swords Dance, Skarmory's already devastating attack is doubled! Brave Bird and Iron Head are for STAB. Although both stab moves aren't very super effective on steel, Skarmory has an extremely powerful coverage move: Rock Smash! To further increase this moves power, Fightinium-Z can be implemented! If not, however, Expert Belt is great for powering up Rock Smash because the only reason you'll ever use it is if it is super effective, given the fact that its base power is way too high. Opponents will expect a Sturdy Skarmory, but they'll regret it if they try to hit it with a physical attack! At the cost of a defense drop, Skarmory's already amazing speed goes through the roof! Then, proceed to sweep entire teams with your +2 attack and +2 speed Skarmory!
Skarmory @ Expert Belt / Life Orb
Ability: Sturdy / Weak Armor
EVs: 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Flash Cannon
- Air Slash
- Hidden Power [Fire] / Hidden Power [Ground]
- Agility / Roost
Special Attacker Skarmory! Skarmory's insane special attack stat is underestimated for some reason, and I think should be used more often. Flash Cannon and Air Slash are for STAB. Hidden Power Fire can pick off Pokémon like Ferrothorn, Celesteela, and Skarmory. Hidden Power Ground, however, hits Heatran and is also super effective on electric and fire types. Agility can be used to allow Skarmory to outspeed anything, and Roost can restore Life Orb recoil. However, if you don't want to recoil at all, Expert Belt is a phenomenal replacement.