The Heavy Core is a rare drop from Ominous Vaults inside Trial Chambers and is required to craft the Mace. The drop rate is low (about 7.5% per Ominous Vault), so a consistent approach and realistic expectations matter as much as combat skill.

Method 1: Standard progression (most reliable)

Step 1: Locate a Trial Chamber. Explore deep underground for large copper-and-tuff structures that generate as “Trial Chambers.” These contain Trial Spawners and Vaults.

Step 2: Acquire the Bad Omen effect. Defeat a Pillager Captain or use an Ominous Bottle to gain Bad Omen; this is required to trigger Ominous Trials.

Step 3: Start an Ominous Trial. Approach a Trial Spawner while under Bad Omen to convert it into an Ominous Spawner and begin the harder encounter.

Step 4: Clear the Ominous Trial. Defeat the waves of mobs. Expect tougher variants and more punishing mechanics than standard Trials.

Step 5: Collect the Ominous Trial Key. Claim the key that appears when the Ominous Trial completes; you need this to open an Ominous Vault.

Step 6: Find an Ominous Vault in the chamber. Look for the distinctive vault block. Ominous Vaults are visually different from standard Vaults.

Step 7: Use the Ominous Trial Key on the Ominous Vault. Unlock the vault to roll its loot. Each Ominous Vault has a chance to drop a Heavy Core.

Step 8: Repeat in the same chamber if trials reset. Trigger additional Ominous Trials for more keys and open more Ominous Vaults in the structure if available.

Step 9: Move on to new chambers when exhausted. Travel to other Trial Chambers to keep rolling new Ominous Vaults and increase total attempts.

Step 10: Bring friends to multiply attempts. Vaults are single-use per player, but multiple players can unlock the same vault. A group multiplies rolls and speeds up progress.

Tips for this method:

  • Preparation matters: strong armor, a shield, a water bucket, food (e.g., golden apples), and ranged options improve survival odds.
  • Know your odds: the probability of not getting a Heavy Core after n Ominous Vaults is P(no core) = (1 − 0.075)^n. For n=20, that’s ~22%; for n=40, ~4.6%.
  • Common pitfall: opening normal Vaults. Heavy Cores come from Ominous Vaults unlocked with Ominous Trial Keys.

Method 2: World copy “seed‑scouting” (time-saver with caveats)

Some players report that Ominous Vault results are fixed by world and vault position. You can scout in a copy to find a vault that yields a Heavy Core, then return to the same vault in your main world.

Step 1: Back up or copy your world. Create a duplicate world to avoid risking your main save, especially in Hardcore.

Step 2: Switch the copy to Creative and locate Trial Chambers. Fly through the underground and mark Trial Chambers with accessible Ominous Vaults.

Step 3: Open Ominous Vaults and note the coordinates that yield a Heavy Core. Test Ominous Vaults in the copy until you see a Heavy Core drop; record precise coordinates of that vault.

Step 4: Return to your main world and travel to the recorded vault. Reach the same vault location under Survival/Hardcore conditions with an Ominous Trial Key.

Step 5: Unlock the vault to attempt the same drop. If loot is predetermined on your edition/patch, you should receive the same Heavy Core result.

Notes for this method:

  • Results can vary by edition and game version; treat this as a practical shortcut, not a guarantee.
  • This approach is useful if you are comfortable using world copies and want to cut down random attempts.

Method 3: Timing the vault preview window (situational, Bedrock‑leaning)

Some players report that on Bedrock Edition, opening an Ominous Vault precisely when the Heavy Core appears in its internal “item carousel” can yield the core more consistently. Others report it doesn’t work (especially on Java) or that patches reduce its effectiveness. Treat this as experimental.

Step 1: Expose a side view of the Ominous Vault. Break surrounding blocks to clearly watch items cycling inside the vault.

Step 2: Observe the item carousel until you see the Heavy Core appear. Watch the rotation cadence; some items may appear twice in succession.

Step 3: Use your Ominous Trial Key the instant the Heavy Core appears. Players report best results if the unlock animation finishes while the Heavy Core is still visible in the window.

Step 4: Reattempt if the result changes at click time. If the item changes immediately, you likely won’t receive the core. Try again with another key when available.

Notes for this method:

  • Reports suggest mixed or no effect on Java, and inconsistent success on Bedrock across updates.
  • Do not rely solely on this; use it as a supplemental attempt while following Method 1.

What to do with a Heavy Core

Craft the Mace. Combine 1 Heavy Core with 1 Breeze Rod at a crafting table to make the Mace. The Mace’s damage scales with fall time and applies strong knockback, giving you a powerful option for Trial Chambers and surface combat.

Optional utility. Placing a Heavy Core under a Note Block produces a snare drum sound, useful for musical builds. Behavior with pistons differs between editions; keep contraptions simple if you build around it.

Preparation checklist

Gear up for Ominous Trials.

  • Armor and shield: aim for high protection and reliable blocking.
  • Mob control: bow or crossbow, and ample arrows to thin crowds safely.
  • Sustain: food, potions, and a water bucket to manage falls and fire.
  • Blocks and tools: quick cover, line‑of‑sight breaks, and pathing.
  • Inventory discipline: keep a free hotbar slot for keys and a clear plan for pickups.

A steady cadence of Ominous Trials and Ominous Vault openings is the only consistently reliable path; seed‑scouting can save time, and timing tricks may help on some Bedrock versions. Stick to the plan, track your attempts, and the Heavy Core will land sooner than it feels.