Why shoot his hat off?

With the lack of posts on this classic, I'd thought I'd lengthen the post roster with a question about the wrap-up at the end of the third act.

Jack finds out that Ben was the mole that leaked the information to the newspaper and started the manhunt with a reward for $10,000.

Jack then pulls his pistol and shoots Ben's hat off before going up to him and celebrating.

Now, I realize the 'dramatic' approach to this scene: "Is Jack mad and about to kill him? *dut-duh-dahhhh!!!*

But, in all honesty, how can you justify this event in real life ?

Had I just sold a spec script to Paramount, thanks to a friend's help, I wouldn't punch him in the face before I cracked open a case of beer.

"Any last words, punk?"
"Yeah, your wife is good in bed."
"So, you're a liar, too?"