Inferno (Magmortar)@Assault Vest / Expert Belt
Role: Wall Breaker / Bulky Sweeper
Ability: Vital Spirit
EVs: 116 HP / 252 Sp. Atk / 140 Sp. Def
- Fire Blast
- Focus Blast
- Psychic / Substitute
Despite its weakness to SR and early-game hazards, Magmortar is a great special Wallbreaker in NU with a very high Sp. Atk. It allows it to deal with bulky Pokemon, such as Audino, with ease.
Maximum investment in Sp. Atk is needed to deal enough damage. Investment in HP and Sp. Def allows it to take certain hits significantly easier. Usually, Assault Vest is preferred, but Expert Belt can be an option to deal more damage. Leftovers is an option, but it isn't as good as those two items. Vital Spirit is meant to counter many Sleep Powder users, such as Lilligant and Vileplume.
Fire Blast is preferred over Flamethrower for instant damage.
Thunderbolt is used for coverage against Water-types.
Focus Blast gives coverage against Rock-types that can wall this set (ex: Rhydon).
Finally, Psychic gives coverage against bulky Fighting-types, such as Gurdurr. Substitute can be used to take advantage of the various switches that Magmortar forces, but you would have to use Expert Belt.