# UNDF: UNDF-2026-000000987
--- a/rts/Sim/Weapons/Weapon.h
+++ b/rts/Sim/Weapons/Weapon.h
@@ -1,6 +1,7 @@
 #ifndef WEAPON_H
 #define WEAPON_H

+#include <unordered_set>
 #include <functional>
 #include <vector>

@@ -46,8 +47,8 @@
 	virtual const float3& GetAimFromPos(bool useMuzzle = false) const { return (useMuzzle? weaponMuzzlePos: aimFromPos); }

-	bool HasIncomingProjectile(int projID) const { return (std::find(incomingProjectileIDs.begin(), incomingProjectileIDs.end(), projID) != incomingProjectileIDs.end()); }
-	void AddIncomingProjectile(int projID) { incomingProjectileIDs.push_back(projID); }
+	bool HasIncomingProjectile(int projID) const { return (incomingProjectileIDs.find(projID) != incomingProjectileIDs.end()); }
+	void AddIncomingProjectile(int projID) { incomingProjectileIDs.insert(projID); }

 public:
 	/// test if the weapon is able to attack an enemy/mapspot just by its properties (no range check, no FreeLineOfFire check, ...)
@@ -203,7 +204,7 @@
 	float3 salvoError;

 	float3 errorVector;
-	std::vector<int> incomingProjectileIDs;
+	std::unordered_set<int> incomingProjectileIDs;

 protected:
 	SWeaponTarget currentTarget;
--- a/rts/Sim/Weapons/Weapon.cpp
+++ b/rts/Sim/Weapons/Weapon.cpp
@@ -724,7 +724,7 @@
 	// NOTE: DependentDied is called from ~CObject-->Detach, object is just barely valid
 	if (weaponDef->interceptor || weaponDef->isShield) {
-		spring::VectorErase(incomingProjectileIDs, static_cast<CWeaponProjectile*>(o)->id);
+		incomingProjectileIDs.erase(static_cast<CWeaponProjectile*>(o)->id);
 	}
 }