The weapon that fires a three-round burst and uses Heavy ammo is the Hemlok.
The Hemlok, officially styled the Hemlok Burst AR, is an assault rifle in Apex Legends. Its defining firing mode is a three-round burst: each trigger pull releases three rounds in rapid succession. It can also be switched to single-fire mode, giving players more control at longer ranges or when conserving ammunition.
The weapon uses Heavy ammo, the ammunition type traditionally associated with harder-hitting bullets and slower projectile behavior than Light ammo. The Hemlok is effective at medium range, where controlled bursts can deliver substantial damage without the sustained recoil of a fully automatic rifle.
The Hemlok is commonly confused with the Prowler because both can fire bursts. The Prowler is an SMG and uses Heavy ammo as well, but its standard burst contains five rounds rather than three. The R-99 is fully automatic and uses Light ammo, while the Flatline is a Heavy-ammo assault rifle with a fully automatic default firing mode.
The Hemlok has appeared in multiple loot-pool and care-package configurations as Apex Legends’ weapon balance has changed over time.