Firearm lubrication

Question
Recently I took my deer rifle to a local gunsmith because of misfiring.  The problem turned out to be a gummy buildup in the bolt.I mentioned to him that locksmiths recommend the use of powdered graphite in locks because it doesn't collect dirt and abrasives that could cause the lock to malfunction or wear prematurely.  I asked him if powdered graphite might be a good lubricant for firearms and he replied that he didn't know and that he had never heard of it being done.  Is there some reason that this isn't done or might it be a good idea?

Answer
I don't use or recommend any powder lubricants because guns still require oil and oil and powder don't mix. A lot of folks will put down WD-40, but I have been using it for 30 years and my Dad before me. I wash down my actions, bores, triggers and everything else with WD-40 and then wipe dry and put lite coat of good gun oil on, never had a failure yet.