I lost my first three walls to behemoth biters. First wall was all gun turrets - the ammo supply collapsed when the attack came from both sides. Second wall was all lasers - the power draw triggered a brownout and the turrets fired slower as my power dropped. Third wall was all flamethrowers - the fuel line was fine but the leading edge of biters walked through the flames before they died. I finally built a mixed defense and the biters never broke through again. Here's what each turret type does and how to combine them.
Turret Comparison
| Turret | Damage per shot | Range | Fire rate | Ammo cost | Phase |
|---|---|---|---|---|---|
| Gun (piercing) | 10 (+60% vs BIG) | 25 tiles | 10/s | Piercing round (iron + copper) | Early-Mid |
| Gun (uranium) | 24 (+60% vs BIG) | 25 tiles | 10/s | Uranium round (238 + 238) | Late |
| Laser | 20 (+20% vs fire) | 22 tiles | 3.2/s | 2.4 MW power | All |
| Flamethrower | ~100+/s (DoT) | 22 tiles | Continuous | Crude oil / heavy oil | Mid-Late |
The raw DPS comparison (at maximum research):
| Turret | DPS (no upgrades) | DPS (max physical/energy upgrades) | Notes |
|---|---|---|---|
| Gun (piercing) | 100 | ~300 | Ammo throughput is the limit |
| Gun (uranium) | 240 | ~750 | Best single-target DPS in the game |
| Laser | 64 | ~250 | Consistent, no ammo logistics |
| Flamethrower | ~500 (area) | ~1,500 | Area effect, stacks with damage upgrades |
Flamethrowers win on raw DPS because they damage everything in an area. Gun turrets win on single-target damage (especially against behemoth biters). Lasers win on logistics convenience.
Early Game Defense (Pre-Oil)
| Turret type | Count per wall segment | Research needed | Pros | Cons |
|---|---|---|---|---|
| Gun turret | 6-8 per side | None | Cheap, hits hard | Ammo logistics |
| Laser | 2-4 | Laser turrets | No ammo | High power draw |
Early wall blueprint (pre-oil):
W W W W W W W W W W W W W W W W (wall layer)
T T T T (gun turrets behind wall)
B B B B B B (belt for ammo)
Feed piercing rounds into the turrets from a belt running behind the wall. One yellow belt of piercing rounds supports ~20 turrets at moderate attack frequency.
Ammo production for early defense: 1 assembling machine making piercing rounds feeds ~10 turrets. At 50 turrets, you need 5 assemblers dedicated to ammo. Automate this before you automate green science.
Mid Game Defense (Blue to Purple Science)
| Turret type | Count per wall segment | Research needed | Pros | Cons |
|---|---|---|---|---|
| Gun (piercing) | 4-6 | Already researched | Handles spitters | Needs ammo belt |
| Laser | 4-6 | Already researched | Handles small/medium alone | Poor vs fire spitters |
| Flamethrower | 2-3 | Flamethrower | Mass AOE clearing | Fuel supply, friendly fire |
Mid-game wall blueprint:
D D . D D . D D . D D . D D . D D (dragon teeth - gaps attract biters)
W W W W W W W W W W (wall)
F F F F F F (flamethrowers behind wall)
T T T T T T (gun turrets behind flamethrowers)
L L L L L L (lasers behind gun turrets)
Dragon teeth design: Place walls in a checkered pattern 4-6 tiles in front of the main wall. Biters path toward the gaps between teeth. Flamethrowers aim at those gaps. The biters walk through fire to reach the wall, taking damage the entire way.
Fuel the flamethrowers: Crude oil works for flamethrowers (you don't need heavy/light). Run an underground pipe from your nearest oil field. One pumpjack feeds ~30 flamethrowers continuously in normal attack mode.
Late Game Defense (Megabase)
| Turret type | Count per wall segment | Research needed | Pros | Cons |
|---|---|---|---|---|
| Gun (uranium) | 6-8 | Uranium ammo | Highest DPS | Expensive ammo |
| Laser | 8-10 | High energy upgrades | Reliable | Enormous power |
| Flamethrower | 4-6 | Damage upgrades | AOE clearing | Needs fuel supply |
Megabase wall blueprint:
D D D D D D D D D D D D D D D D D D D D (dense dragon teeth, 3-4 layers)
W W W W W W W W W W W W W W (2-thick wall)
F F F F F F F F (flamethrowers, max density)
T T T T T T T T (gun turrets with uranium)
L L L L L L L L (lasers, max density)
R R R (roboort behind for repair)
B B B (buffer chest with replacement walls + ammo)
Uranium ammo production for megabase: One centrifuge on uranium processing feeds ~50 gun turrets. At 500 turrets around your perimeter, you need 10 centrifuges running. Automate this as part of your nuclear fuel production.
Robotic wall repair: Place a roboport behind each wall segment. Fill a buffer chest with replacement walls, repair packs, and ammo. Construction robots automatically replace damaged walls and refill turrets. Without this, behemoth biters will breach a weakened section in one attack.
The Pollution Strategy - Build or Destroy
Two approaches to biter defense, and they're not equally efficient:
| Strategy | Effort | Effectiveness | UPS impact |
|---|---|---|---|
| Wall + turret perimeter | Medium | Good for 1-5 hours | Medium (entity updates) |
| Clear nests outside pollution | High initial, then zero | Best | Zero (no attacks) |
The "clear the cloud" strategy: For a megabase, walling the entire pollution cloud is impractical (it's huge). Instead, clear all biter nests within your pollution cloud using a rocket-launcher-equipped tank or spidertron. Once clear, expand your walls to the new clear boundary. Repeat every few hours as the cloud expands.
The "continuous perimeter" strategy: Build a wall around your entire base. This is simpler but requires constant ammo/fuel supply to every wall segment. Works well for bases under 100 SPM.
Power Consumption of Turrets
Laser turrets consume 2.4 MW each during firing. A wall segment with 8 lasers firing continuously = 19.2 MW draw. Flamethrowers and gun turrets consume negligible power.
Power budget for 8-laser wall segment:
- 8 lasers firing 50% of the time = 9.6 MW average
- 2,400 laser turrets per 1 GW solar field
- A massive behemoth attack can pull this spike 5-10x for 30 seconds
Buffer solution: Connect turret power through an accumulator bank. The accumulators absorb the firing surge while your main grid stays stable. A cluster of 50 accumulators near the wall provides ~10 seconds of full laser-fire buffer.
Bottom Line
Factorio defense has three phases. Early game: gun turrets with piercing ammo. Mid game: add flamethrowers with dragon teeth. Late game: uranium ammo + laser + flamethrower + robot repair. In all phases, the best defense is clearing nests outside your pollution cloud.
Numbers to remember:
- Gun (piercing): 10/s shots, 10 damage base, needs ammo belt
- Laser: 3.2/s shots, 20 damage base, 2.4 MW draw
- Flamethrower: ~100/s AOE damage, needs crude oil pipe
- 1 assembling machine feeds ~10 turrets (piercing)
- 1 pumpjack feeds ~30 flamethrowers
- Dragon teeth = checkered wall pattern 4-6 tiles in front of main wall
Related: Artillery Guide | Early Game Defense | Flamethrower Defense Guide
Community Verification & Resources
- Official Factorio Wiki -- Turret - exact stats and damage formulas
- Official Factorio Wiki -- Damage - biter armor and damage type resistance
- Reddit -- Gun vs Laser vs Flamethrower - community-tiered discussion on best defense configurations
- Reddit -- Wall Blueprints - community-shared wall designs for all game phases