Do you know if the dial is locked or just the "Day-Lock"? It's easier to get into them if only the Day-Lock is locked. A friend of mine , who sold gun safes, says that if only the day-lock is used, you can just drill out the tumblers in the key lock and turn the outside dial to be able to open the door. At this point, you might not know if only the Day-Lock is in use. If your dial is set on zero, then that might be a clue that only the day-lock is set and not the tumblers. Sadly, most owners only use the day-lock and later regret their actions. Now, understand that I am not aware of the quality of safe you have. .....
My safe is one of a high-end safes and it came with two keys. A few years back, I lost one of them and when I tried to get a spare from a reputable lock smith, he said he could not legally duplicate it and he did not have that base pattern. Now, I also know that most gun safe manufactureres do not make the lock itself but instead, buy them from an outside source, in lots. ...
By my measure, A" locksmith is still your best bet. ....
Be Safe !!!