You got me.
3 seconds sound clip from the Die Hard (1988) movie soundboard.
You can hear this line at 02:01:08 in the Blu-ray version of the movie.
Quote context
[...]
- Why did you have to nuke the whole building, Hans?
- That's Gary Cooper, asshole.
- You'd have made a pretty good cowboy yourself, Hans.
- Oh, yes. What was it you said to me before?
[...]