The phrase comes from crossbow archery, where a 'bolt' is a type of arrow, symbolizing used-up effort. After applying to dozens of jobs without success, I felt I had shot my bolt.
Pro Tip 2/3
Common Misuse
Don't confuse it with 'shooting oneself in the foot', which means causing self-harm by mistake. He didn't shoot himself in the foot; he simply had shot his bolt with nowhere to go.
Pro Tip 3/3
Use in Failure
It's often used when someone has failed after giving their all, not just when they're tired. The team had shot their bolt in the first half and lost the game.