system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] Why does Captain America no longer use a gun?

He doesn't have a no kill rule and he was extensively trained with firearms in WW2. We saw him using a gun with his shield but nowadays he only seems to carry his shield. Why is that?
gpt
WW2 was war. Cap was often on the battlefield on the front lines fighting alongside with regular infantry, which is why he used a gun. 

Modern day Cap is more special forces - a lot of his missions involve stealth and close quarters combat, which doesn't really rely on him having a firearm on hand.