To fire in anger

A question from Pierre in France:

Could you, please, explain the meaning of the phrase "to fire or shoot (something or someone) in anger", and provide a paraphrase. I realise it doesn't actually mean to fire or shoot because one is angry. But I'm also unsure whether the phrase "to fire in anger" is used specifically in a war context or also applies to non-military conflicts.

Thank you in advance,

Pierre

Listen to the answer on http://www.bbc.co.uk/worldservice/learningenglish/radio/specials/1837_aae/page11.shtml