would pooring water on barrel help cooling?

Also: You ever notice heat waves coming off a hot blacktop road in summer? If you are using a scope and your barrel is hot enough, you can see these heat threads through the scope, and it will throw off your accuracy simply because of the optical changes (not to mention your poor mini barrel turning into a pool of molten metal). What can you expect from an $8 barrel?

You have to think about the additional weight that a good barrel would add to the gun. A nice chrome lined steel barrel will weigh a good deal more than the tinfoil one from the factory.