This core basically uses Hariyama's capabilities to whittle down Pinsir and Swellow's checks, which soon letting the two sweep or at least wallbreak for the core.
Pinsir- Pinsir's ability to hit common physical walls like weezing with EQ makes it a good set-up sweeper, though its mediocre speed makes it vulnerable to faster threats
Hariyama- Hariyama is good check to fire/ice type moves in this meta, which threatens pinsir and swellow, and AV is a good item to make Hariyama a decent spd wall.
Swellow- Swellow's speed makes it the fastest pokemon in NU (bar scarfed mons). Swellow is pretty much of a good speed control in this team, given that Pinsir and Hariyama only has a decent speed tier. Also deals with faster threats like Scyther,Pyroar,Non-Scarf Jynx and etc.
Pinsir @ Lum Berry
Ability: Mold Breaker
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Swords Dance
- X-Scissor
- Stone Edge
- Earthquake
Hariyama @ Assault Vest
Ability: Thick Fat
EVs: 252 Atk / 128 Def / 128 SpD
Adamant Nature
- Close Combat
- Bullet Punch
- Fake Out
- Knock Off
Swellow @ Choice Specs || Flame Orb / Toxic Orb
Ability: Scrappy || Guts
EVs: 252 SpA / 4 SpD / 252 Spe || 252 atk / 4 SpD /252 Spe
Timid|| Jolly Nature
- Boomburst || Facade
- Heat Wave || Quick Attack
- U-turn
- Sleep Talk || Brave Bird
(Swellow's Set depends on the team's layout)
Ability: Mold Breaker
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Swords Dance
- X-Scissor
- Stone Edge
- Earthquake
Hariyama @ Assault Vest
Ability: Thick Fat
EVs: 252 Atk / 128 Def / 128 SpD
Adamant Nature
- Close Combat
- Bullet Punch
- Fake Out
- Knock Off
Swellow @ Choice Specs || Flame Orb / Toxic Orb
Ability: Scrappy || Guts
EVs: 252 SpA / 4 SpD / 252 Spe || 252 atk / 4 SpD /252 Spe
Timid|| Jolly Nature
- Boomburst || Facade
- Heat Wave || Quick Attack
- U-turn
- Sleep Talk || Brave Bird
(Swellow's Set depends on the team's layout)