rain v.

ご存知のことかと思いますが、こういうrainの用法もあることを記事を読んで知りました。「（…を）雨のように浴びせかける」（"To send or pour down, shower" -The American Heritage Dictionary of the English Language）という意味ですね。
考えてみるとまったく同じ表現が日本語にもありますね。ひょっとしたら英語から入ってきたものなのでしょうか。ともあれそんなことは絶対に起きて欲しくないと思います。（GP）

As rhetoric heats up, North Koreans ready to 'rain bullets on the enemy'

(CNN) -- The 80-year-old North Korean war vet says he's been holding onto a bullet he didn't get to fire when his country declared a truce with its neighbor 60 years ago.

Now -- if North Korean state media is to be believed -- the man is itching to do so.

"I am still keeping a bullet that I failed to fire at a trench in the 1950s because the U.S. imperialists and their stooges signed an armistice agreement," the man is quoted as saying in Rodong Sinmun, the official newspaper of the ruling Workers' Party.

"Send me to the trench. Give me a rifle. I want to rain bullets on the enemy to my heart's content."

http://edition.cnn.com/2013/03/12/world/asia/koreas-tensions/index.html?hpt=hp_t2