while it's not optimal and ~generally~ inferior to physical, it's legit.
252 SpA Choice Specs Swellow Boomburst vs. 252 HP / 4 SpD Eviolite Doublade: 111-131 (34.4 - 40.6%) -- guaranteed 3HKO
252 SpA Choice Specs Swellow Boomburst vs. 252 HP / 0 SpD Qwilfish: 307-363 (91.9 - 108.6%) -- 50% chance to OHKO
252 SpA Choice Specs Swellow Boomburst vs. 4 HP / 0 SpD Carracosta: 135-159 (46.5 - 54.8%) -- 66% chance to 2HKO
252 SpA Choice Specs Swellow Boomburst vs. 252 HP / 0 SpD Weezing: 255-301 (76.3 - 90.1%) -- guaranteed 2HKO after Black Sludge recovery
252 SpA Choice Specs Swellow Boomburst vs. 252 HP / 0 SpD Dusknoir: 147-174 (50 - 59.1%) -- 76.2% chance to 2HKO after Leftovers recovery
252 SpA Choice Specs Swellow Boomburst vs. 252 HP / 4 SpD Steelix: 134-158 (37.8 - 44.6%) -- guaranteed 3HKO after Leftovers recovery
it bops the shit out of some traditional bird switch-ins making it a fantastic partner to other physical sweepers, has more longevity than physical sets (since you don't get owned by status dmg / SR as much) and can still be a great cleaner with boomburst. i paired it with variants of durant and wrecked shit on the ladder with it in an otherwise mediocre team under the alt STR8 GARB if any of you played me. the matches i lost in involved five straight durant misses and a critical hit + three flinches with a scarf zen headbutt mesprit. this is the set i used:
Swellow @ Choice Specs
Ability: Scrappy
EVs: 252 Spd / 252 SAtk / 4 SDef
Timid Nature
IVs: 0 Atk
- Boomburst
- U-turn
- Defog
- Air Slash
boomburst is the only move you should usually click. u-turn is alright if you predict certain switch-ins; it's helpful when you're playing against stuff that swellow can't really break through, like probopass. i use defog over hidden power ground - hp ground is literally only useful for the 4x resists like probopass and until those are more common i really can't justify using it whereas you can defog stuff like sticky web away for your partner if that's more important than getting off a boomburst at that point in time. air slash is literally only for virizion (boomburst only 2hkoes) and the flinch chance.
modest also catches everything up to durant (not archeops, sceptile) and provides a decent chunk of power and pushes a few 3HKOes to 2HKOes. examples of modest:
252+ SpA Choice Specs Swellow Boomburst vs. 4 HP / 0 SpD Sigilyph: 252-297 (88.1 - 103.8%) -- 25% chance to OHKO
252+ SpA Choice Specs Swellow Boomburst vs. 4 HP / 0 SpD Feraligatr: 244-288 (78.2 - 92.3%) -- 37.5% chance to OHKO after Stealth Rock
252+ SpA Choice Specs Swellow Air Slash vs. 252 HP / 0 SpD Gourgeist-Super: 284-336 (75.9 - 89.8%) -- guaranteed 2HKO after Leftovers recovery
252+ SpA Choice Specs Swellow Boomburst vs. 4 HP / 0 SpD Durant: 186-219 (72 - 84.8%) -- guaranteed 2HKO