What it does
Heavy Slam is a Steel-type physical move with variable Base Power determined by how much heavier the user is compared to the target:
- Less than 2× heavier: 40 BP
- 2× to under 3×: 60 BP
- 3× to under 4×: 80 BP
- 4× to under 5×: 100 BP
- 5× or more heavier: 120 BP
The 120 cap is competitive with the top tier of Steel-type physical options. Compare to Iron Head at a flat 80 BP — when the weight condition is met, Heavy Slam wins on raw power by a significant margin, and it has 100% accuracy just like Iron Head.
The whole equation is about the user's absolute weight. Orthworm, Steelix, Aggron are among the heaviest Steel-types around. Against the majority of lighter or mid-weight targets, the ratio easily clears 5×, guaranteeing 120 BP. Lighter Steel-types against heavier opponents might only get 80 or less — this move is not universally good, it's specifically good on very heavy Pokémon.
Who runs it
Orthworm (70%) is the flagship user. Enormous body weight, Earth Eater for Ground immunity, and Heavy Slam as its main Steel-type damage source. Against most opponents, it hits the 100–120 BP tier reliably.
Aggron (63%) has the weight to back up the move. Heavy Slam is its primary Steel STAB output, with 120 BP available against the lighter half of the field.
Mudsdale (46%) is a Ground-type that learns Heavy Slam. Extremely heavy, it can land in the high BP tiers and adds a Steel coverage line alongside its Ground STAB.
Avalugg (23%) is Ice-type but very heavy. Heavy Slam gives it a way to threaten targets that its Ice moves can't cover — particularly relevant when facing Steel or Rock types that resist Ice.
Bastiodon (17%), Hippowdon (14%), Steelix (8%), and Rhyperior (4%) all have the weight to make this work — their lower usage reflects lower overall pick rates rather than a problem with the move.
How to use it
Before you commit to Heavy Slam, check the weight matchups at team building time. What are the common Pokémon in the current meta? How heavy are they relative to your user? That ratio is what decides whether you're consistently hitting 120, 100, or lower.
In doubles, Heavy Slam is single-target. Use it into Ice, Rock, and Fairy types where Steel STAB matters. Those are the matchups where you want the high-BP hit rather than wasting it against Steel- or Water-resistant targets.
The Iron Head comparison matters here. Iron Head's 30% flinch chance has genuine doubles utility — locking one target out of a turn is real. Heavy Slam has no secondary effect, but it hits harder under the right conditions. If your team already has flinch tools or other disruption, take the power.
Tips & strategy
The hard counter to Heavy Slam is fighting a very heavy target. Against something like an oversized Rock-type or a massive defensive wall that outweighs your user, the BP can drop to 40 — effectively a waste. Keep a backup move available, or just run Iron Head in matchups where you're not confident about the weight ratio.
Orthworm and Aggron consistently hit 100–120 BP against most of the meta. If you're unsure whether a target is light enough, 80 BP is your conservative floor — still workable, never catastrophic.
In Trick Room teams, heavyweight Steel-types fit naturally — low Speed means they benefit from the inverted priority. Heavy Slam pairs cleanly with that archetype: when Trick Room is up, you move first, and you hit hard.