system
Given the following post, respond as if you're commenting on Reddit:
human
[Captain America: The Winter Soldier] WTF didn't Bucky kill Steve after taking his shield?

In Captain America: TWS Bucky snipes Nick Fury and is being chased by Captain America. Around the end of the chase Captain America throws his shield at Bucky to stop him from escaping and Bucky catches it. I mean Bucky's holding Captain America's most significant weapon and or defence and it would take seconds from him to shoot Cap but he chooses to throw the shield right back to Steve and not SHOOT HIM.

Why would Bucky return the shield?

Why would Bucky not shoot Cap on the spot?
gpt
He didn't "return" the shield, he threw it back at him as a weapon.  He took out his target and was in escape mode. Bucky didn't know who Captain America was and didn't know he would be a long term threat.