As a gunsmith, you should know what the market can bear and then set your rates appropriately. I charge $40 per hour billable in half hours periods, if it takes me 40 minutes I charge $40. That said, many times I don't charge what I should for the amount of time spent on the repair but many times it is because I enjoyed working on the firearm so I give the person a break. Sometimes it's like collecting Rugers, the fun is in the hunt (parts, diagrams, how to's, etc.), the actual hands on the gun, and then seeing the finished product and the look on the owners face when you give them back their (in some cases what started out as a basket case) gun.