I think the bolt in that idiom is shot from a crossbow. I'll check....

shoot one's bolt

Also, shoot one's wad. Do all within one's power; exhaust one's resources or capabilities. For example, They were asking for more ideas but Bob had shot his bolt and couldn't come up with any , or Don't shoot your wad with that article or you won't have any material for the sequels. The first expression comes from archery and referred to using up all of one's bolts (short, heavy arrows fired with a crossbow); it was a proverb by the 1200s. The colloquial variant, dating from about 1900, comes from gambling and refers to spending all of a wad of rolled-up banknotes.

Crossbow - bolt - exhaustion. Yup. It took me a long time, checking and writing, to do that blog with a distillation of my experiences of investigative journalism. So I didn't get to blog yesterday because I was getting more techy help from my genius grandson and then I had an unexpected welcome guest for lunch and then - of course - the Oscars, fro the first red carpet to the very end.

Well, I don't have to tell you. You know how time gets away from one. What happened today?

I think I finally have a slight grip on the screenplay. I think I can write the penultimate draft this week.

We'll see.