> ## Documentation Index > Fetch the complete documentation index at: https://docs.battlecode.cam/llms.txt > Use this file to discover all available pages before exploring further. # Turrets > Defensive and offensive combat units — gunner, sentinel, breach, and launcher. Every turret **except the launcher** faces in one of **8 directions**. ## Ammo Gunners, sentinels, and breaches require **ammo** to fire. Ammo is simply a stack of resources sitting inside the turret — each shot consumes a fixed number of resources from that stack (see per-turret tables below). Launchers do not use ammo. Ammo must be fed to turrets via conveyors, an adjacent harvester, an adjacent foundry, or a bridge targeting the turret's tile, from any direction except the direction the turret is facing. Diagonal turrets can be fed from all four sides. Ammo-based turrets can hold up to one stack of one resource type and only accept incoming resources when completely empty. If a builder bot is standing on a building, turret attacks on that tile hit **only the builder bot**. Raw axionite fed into a turret is **destroyed**. Only the ammo types listed below have any effect. Breach turrets additionally accept and destroy **all** resource types (including titanium) — see [Breach](#breach). ## Gunner Gunner Has a vision radius of √13. Fires along the forward ray up to range. Empty tiles and markers do **not** block line of sight. Markers are still targetable. Walls block the ray but are not targetable. Builder bots and non-marker buildings are both targetable and blocking, so nothing beyond the first such blocker is legal. Using refined axionite as ammo deals **25 damage** instead of 10. Markers are the only occupied tiles that do **not** block a gunner. Walls block but are not targetable. Builder bots and non-marker buildings are both targetable and blocking. `c.get_gunner_target()` returns the closest **targetable** occupied tile on the forward line. It may return a marker even if a farther legal target also exists behind that marker. Gunners can rotate to any direction with `c.rotate(direction)`. This costs **10 Ti** from the global pool and applies a **1-turn cooldown**. Use `c.can_rotate(direction)` to preflight the move. | Property | Value | | ------------- | ----------------------------- | | HP | 40 | | Base cost | 10 Ti | | Scaling | 10% | | Damage | 10 (25 with refined axionite) | | Reload | 1 round | | Ammo per shot | 2 | | Vision r² | 13 | | Attack r² | 13 (same as vision) | Gunner range — cardinal direction Gunner range — diagonal direction ## Sentinel Sentinel High range support turret. Can hit all tiles within **1 king move** (Chebyshev distance) of the straight line in its facing direction, within vision range. Using refined axionite instead of titanium as ammo adds **+5 to the action and move cooldown** of any unit directly hit — acting as a stun. | Property | Value | | ------------- | ------------------- | | HP | 30 | | Base cost | 30 Ti | | Scaling | 20% | | Damage | 18 | | Reload | 3 rounds | | Ammo per shot | 10 | | Vision r² | 32 | | Attack r² | 32 (same as vision) | Sentinel range — cardinal direction Sentinel range — diagonal direction Sentinels with refined axionite ammo still disrupt builder bots by delaying both movement and actions. ## Breach Breach Very high damage with **splash**. Attacks in a **180° cone** in the facing direction. | Property | Value | | ------------- | ------------------------------------------- | | HP | 60 | | Base cost | 15 Ti, 10 Ax | | Scaling | 10% | | Damage | 40 direct + 20 splash (8 surrounding tiles) | | Reload | 1 round | | Ammo per shot | 5 (refined axionite only) | | Vision r² | 2 | | Attack r² | 24 | Breach range — cardinal direction Breach range — diagonal direction Breach turrets accept **all** resource types, but only refined axionite is stored as ammo. Titanium and raw axionite delivered to a breach are consumed and **destroyed** on receipt. This prevents resources from backing up on conveyors feeding a breach. Breach turrets have **friendly fire** on the splash damage (8 surrounding tiles). They do not damage themselves. ## Launcher Launcher Picks up and **throws adjacent builder bots** to a target tile within range. The target tile must be bot-passable. Unlike other turrets, launchers have **no facing direction** and do not use ammo. | Property | Value | | --------- | ------------------- | | HP | 30 | | Base cost | 20 Ti | | Scaling | 10% | | Reload | 1 round | | Vision r² | 26 | | Attack r² | 26 (same as vision) | Launcher range — blue is vision, red is throw range ```python theme={"dark"} # Build a launcher (no direction needed) c.build_launcher(pos) # Launch a builder bot to a distant position if c.can_launch(bot_pos, target_pos): c.launch(bot_pos, target_pos) ``` ## Querying turret geometry `c.get_attackable_tiles()` returns the raw geometric attack pattern for the turret you are controlling, and `c.get_attackable_tiles_from(position, direction, turret_type)` returns the same pattern for a hypothetical turret at any position — callable from any controller. Both ignore ammo, cooldown, occupancy, blockers, and other legality checks. To check whether a shot is actually legal right now, use `c.can_fire(target)` on a real turret, or `c.can_fire_from(position, direction, turret_type, target)` to test a hypothetical shot against the current map's range and obstruction rules. See the [Controller reference](/api/controller) for full method signatures.