This Jirachi was in my team for a while and I did nice job, really.
Jirachi
[SET]
Name: Attacking Lead
Move 1: Stealth Rock
Move 2: Iron Head
Move 3: Fire Punch/Zen Headbutt
Move 4: U-turn
Nature: Jolly
Item: Leftovers
EVs: 252 Atk/252 Spd/4 HP
Why this should be on-site:
- Sets up dangerous EntryHazard, as nearly any Lead.
- Can deal some massive damage to common leads.
- Also serves as a late-game sweeper.
- Decent bulk, even without defensive EVs, allows it to live some dangerous attack (Metagross' Earthquake, for example)
- Serene Grace gives big chances of flinches and burns.
- Quickly switches out, OHKOing Celebi, gives big damage to Azelf, but not to a Sash.
Additional comments:
- There's also an option of giving some defense to it, but it may be not as powerful to kill some pokes.
- Zen Headbutt gives some flinches, while Fire Punch can burn opponent. But with Zen Headbutt you won't kill Metagross, while Swampert laughs at you, when you're running Fire Punch.
Teammates & counters:
- Pokemon with Grass moves, when using Fire Punch, while Zen Headbutt version needs Fire/Ground types support.
- Sand Stream can also help to destroy Sashes, for example. It doesn't also hurt Jirachi.
- Metagross walls the set with Zen Headbutt, while Swampert with Fire Punch (tell it third time :P)
- Scizor also works without Fire Punch.
- Zapdos. Whatever it has.

Jirachi
[SET]
Name: Attacking Lead
Move 1: Stealth Rock
Move 2: Iron Head
Move 3: Fire Punch/Zen Headbutt
Move 4: U-turn
Nature: Jolly
Item: Leftovers
EVs: 252 Atk/252 Spd/4 HP
Why this should be on-site:
- Sets up dangerous EntryHazard, as nearly any Lead.
- Can deal some massive damage to common leads.
- Also serves as a late-game sweeper.
- Decent bulk, even without defensive EVs, allows it to live some dangerous attack (Metagross' Earthquake, for example)
- Serene Grace gives big chances of flinches and burns.
- Quickly switches out, OHKOing Celebi, gives big damage to Azelf, but not to a Sash.
Additional comments:
- There's also an option of giving some defense to it, but it may be not as powerful to kill some pokes.
- Zen Headbutt gives some flinches, while Fire Punch can burn opponent. But with Zen Headbutt you won't kill Metagross, while Swampert laughs at you, when you're running Fire Punch.
Teammates & counters:
- Pokemon with Grass moves, when using Fire Punch, while Zen Headbutt version needs Fire/Ground types support.
- Sand Stream can also help to destroy Sashes, for example. It doesn't also hurt Jirachi.
- Metagross walls the set with Zen Headbutt, while Swampert with Fire Punch (tell it third time :P)
- Scizor also works without Fire Punch.
- Zapdos. Whatever it has.