private void CreateBullet(params BulletProperties[] properties)
        {
            var id         = BulletProperties.GetId(properties);
            var projectile = new ProjectileBuiltBullet(properties);

            AddProjectile("builtbullet-" + id, projectile);
            AddItem("itembuiltbullet-" + id, new ItemBuiltBullet(properties, projectile));
        }