diff --git a/server/gameserver/collision.cc b/server/gameserver/collision.cc
index 5f3a4302..2a8c2349 100644
--- a/server/gameserver/collision.cc
+++ b/server/gameserver/collision.cc
@@ -13,6 +13,8 @@
 #include "mt/Map.h"
 #include "mt/MapThing.h"
 
+static const float GUN_HEIGHT = 3.0f;
+
 bool Collision::CheckBullet(IBullet* bullet, Creature* c)
 {
     glm::vec3 bullet_real_pos = bullet->GetPos().ToGlmVec3() - bullet->GetDir() * bullet->GetHitRadius();
@@ -22,15 +24,15 @@ bool Collision::CheckBullet(IBullet* bullet, Creature* c)
     }
     bool ret = a8::IntersectCylinderCylinder
         (
-         bullet_real_pos, bullet_hit_radius * 1.0, 10,
-         c->GetPos().ToGlmVec3(), c->GetHitRadius(), 10
+         bullet_real_pos, bullet_hit_radius * 1.0, GUN_HEIGHT,
+         c->GetPos().ToGlmVec3(), c->GetHitRadius(), GUN_HEIGHT
          );
     if (!ret) {
         bullet_real_pos = bullet->GetPos().ToGlmVec3() - bullet->GetDir() * (bullet->GetHitRadius() - 2);
         ret = a8::IntersectCylinderCylinder
             (
-             bullet_real_pos, bullet_hit_radius * 1.0, 10,
-             c->GetPos().ToGlmVec3(), c->GetHitRadius(), 10
+             bullet_real_pos, bullet_hit_radius * 1.0, GUN_HEIGHT,
+             c->GetPos().ToGlmVec3(), c->GetHitRadius(), GUN_HEIGHT
              );
     }
     return ret;
@@ -49,14 +51,14 @@ bool Collision::CheckBullet(IBullet* bullet, Entity* e)
             auto wobj = ob->init_args->Get<std::shared_ptr<mt::WorldObject>>(0);
             return a8::IntersectCylinderCylinder
                 (
-                 bullet_real_pos, bullet->GetHitRadius() * 1.0, 10,
-                 e->GetPos().ToGlmVec3(), std::max(wobj->size.x/2.0f, wobj->size.z/2.0f), 10
+                 bullet_real_pos, bullet->GetHitRadius() * 1.0, GUN_HEIGHT,
+                 e->GetPos().ToGlmVec3(), std::max(wobj->size.x/2.0f, wobj->size.z/2.0f), GUN_HEIGHT
                  );
         } else {
             return a8::IntersectCylinderCylinder
                 (
-                 bullet_real_pos, bullet->GetHitRadius() * 1.0, 10,
-                 e->GetPos().ToGlmVec3(), ob->meta->width(), 10
+                 bullet_real_pos, bullet->GetHitRadius() * 1.0, GUN_HEIGHT,
+                 e->GetPos().ToGlmVec3(), ob->meta->width(), GUN_HEIGHT
                  );
         }
     }