diff --git a/server/gameserver/bullet.cc b/server/gameserver/bullet.cc
index 1a3bbeb..c973f18 100644
--- a/server/gameserver/bullet.cc
+++ b/server/gameserver/bullet.cc
@@ -32,11 +32,7 @@ void Bullet::Initialize()
 
 void Bullet::Update(int delta_time)
 {
-#ifdef RAY_DETECTION
     RayDetectionUpdate();
-#else
-    FrameDetectionUpdate();
-#endif
 }
 
 void Bullet::RecalcSelfCollider()
@@ -225,62 +221,3 @@ void Bullet::RayDetectionUpdate()
         }
     }
 }
-
-void Bullet::FrameDetectionUpdate()
-{
-    pos = pos + dir * gun_meta->i->bullet_speed() / (float)SERVER_FRAME_RATE;
-    float distance = (pos - born_pos).Norm();
-    if (room->OverBorder(pos, gun_meta->i->bullet_rad())) {
-        if (IsBomb()) {
-            ProcBomb();
-        } else {
-            room->RemoveObjectLater(this);
-        }
-    } else {
-        room->grid_service.MoveBullet(this);
-        std::set<Entity*> objects;
-        for (auto& grid : grid_list) {
-            for (Human* hum: grid->human_list) {
-                if (hum != player && !hum->dead &&
-                    (hum->team_id == 0 || player->team_id != hum->team_id)) {
-                    if (TestCollision(hum)) {
-                        objects.insert(hum);
-                    }
-                }
-            }
-            for (Entity* entity : grid->entity_list) {
-                switch (entity->entity_type) {
-                case ET_Obstacle:
-                case ET_Building:
-                    {
-                        if (TestCollision(entity)) {
-                            objects.insert(entity);
-                        }
-                    }
-                    break;
-                default:
-                    {
-                    }
-                    break;
-                }
-            }
-        }//end for
-        float bullet_range = gun_meta->i->range();
-        if (gun_upgrade_meta && gun_upgrade_meta->attr[EA_ShotRange] > 0) {
-            bullet_range += gun_upgrade_meta->attr[EA_ShotRange];
-        }
-        if (!objects.empty() || distance > bullet_range ||
-            (IsBomb() && meta->i->_inventory_slot() != 4 && distance >= fly_distance)
-            ) {
-            if (IsBomb()) {
-                ProcBomb();
-            } else {
-                deleted = true;
-                if (!objects.empty()) {
-                    OnHit(objects);
-                }
-                room->RemoveObjectLater(this);
-            }
-        }
-    }
-}
diff --git a/server/gameserver/bullet.h b/server/gameserver/bullet.h
index 0664fbf..790d3bd 100644
--- a/server/gameserver/bullet.h
+++ b/server/gameserver/bullet.h
@@ -38,7 +38,6 @@ class Bullet : public Entity
     void ProcBomb();
     bool IsBomb();
     void RayDetectionUpdate();
-    void FrameDetectionUpdate();
 
 private:
     CircleCollider* self_collider_ = nullptr;