Are there rules for selecting wire gauge for single-pulse applications?
The resistance of the wire has two primary effects. The first is that it causes a voltage drop at the load, and this is independent of the duty cycle. The second is that it causes the wire to heat up, which can cause it to fail.

In general, wiring should be conservatively rated in all applications, because you really don't want the wire itself to be the point of failure, even under fault conditions, such as excessive duty cycle or overcurrent. The wire has to withstand the fault until the protection gear has time to operate.