diff --git a/server/gameserver/bullet.cc b/server/gameserver/bullet.cc
index c973f18..3003692 100644
--- a/server/gameserver/bullet.cc
+++ b/server/gameserver/bullet.cc
@@ -32,7 +32,11 @@ void Bullet::Initialize()
 
 void Bullet::Update(int delta_time)
 {
+#if MAP_SERVICE
+    MapServiceUpdate();
+#else
     RayDetectionUpdate();
+#endif
 }
 
 void Bullet::RecalcSelfCollider()
@@ -221,3 +225,66 @@ void Bullet::RayDetectionUpdate()
         }
     }
 }
+
+void Bullet::MapServiceUpdate()
+{
+    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);
+                    }
+                }
+            }
+        }//end for
+#if 1
+        {
+            std::set<ColliderComponent*> colliders;
+            room->map_service.GetColliders(pos.x, pos.y, colliders);
+            for (ColliderComponent* collider : colliders) {
+                if (TestCollision(collider)) {
+                    objects.insert(collider->owner);
+#if 0
+                a8::XPrintf("%d,%d collider:%d,%d \n",
+                            {
+                             pos.x,
+                             pos.y,
+                             collider->owner->pos.x,
+                             collider->owner->pos.y
+                            });
+#endif
+                }
+            }
+        }
+#endif
+        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 790d3bd..2238439 100644
--- a/server/gameserver/bullet.h
+++ b/server/gameserver/bullet.h
@@ -38,6 +38,7 @@ class Bullet : public Entity
     void ProcBomb();
     bool IsBomb();
     void RayDetectionUpdate();
+    void MapServiceUpdate();
 
 private:
     CircleCollider* self_collider_ = nullptr;
diff --git a/server/gameserver/room.cc b/server/gameserver/room.cc
index 0a11120..ad0e204 100644
--- a/server/gameserver/room.cc
+++ b/server/gameserver/room.cc
@@ -608,7 +608,10 @@ void Room::CreateBullet(Human* hum, Weapon* weapon,
     bullet->Initialize();
     AddObjectLater(bullet);
     grid_service.AddBullet(bullet);
+#if MAP_SERVICE
+#else
     bullet->movement->RayDetection();
+#endif
 }
 
 void Room::RemoveObjectLater(Entity* entity)
@@ -844,8 +847,13 @@ void Room::UpdateGas()
     switch (gas_data.gas_mode) {
     case GasInactive:
         {
+#if 0
+            if (frame_no - gas_data.gas_start_frameno >=
+                3 * SERVER_FRAME_RATE) {
+#else
             if (frame_no - gas_data.gas_start_frameno >=
                 MetaMgr::Instance()->gas_inactive_time * SERVER_FRAME_RATE) {
+#endif
                 gas_data.gas_mode = GasJump;
                 gas_data.gas_start_frameno = frame_no;
                 if (human_hash_.size() < ROOM_MAX_PLAYER_NUM) {