It was the French. Even if they were outgunned and
it would be foolish to fight, they would fire one
shot, because if they didn't their boss, Napoleon,
would punish them.

So they saying was, "One shot--for honor".

"Brian" wrote

I'll go for the obvious. One of the wars France was in.

"N1EE" wrote

What country was known for firing one shot
and then surrendering.

Bart Senior