system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: There is no practical reason that guns should be black.

There are some hunting rifles and rifles for children that are neon orange and pink. The majority of guns (rifles and handguns) are black though. Guns should be required to be neon safety orange. This would allow police officers to more easily identify firearms, and recreation gun owners should have no reason to objection to this. 

This would have to affect toys' colors, but that would be easier to regulate colors of than real firearms. Toys would no longer be able to be the specified color. 

What reason is there that guns are almost all black? 

I would have no objection to a hunting rifle ( let's say a 12 gauge) being brown for camouflage purposes.
gpt
Paint is something that can burn on the gun barrel and gum up moving parts.  For these parts of the gun, it makes sense for them to be bare metal or coated with a lubricating finish.  In most cases, the metal used in the gun is naturally black, so refraining from treating it at all leaves it as black.