>Not paying into social security would very likely lead to better outcomes for me, but not for society as a whole.

You should get some of that money back. Also, by not paying, you would be fined by the government. It's ultimately not overall a benefit to you.

>Edit: The current gun rights debate in the USA is if making it more difficult for hobby marksman is worth the collective safety.

Thinking about the collective, as suggested, doesn't make any sense.

Individuals responsibly owning and carrying firearms is self-beneficial and prosocial.

Individuals irresponsibly owning and misusing firearms is self-harming and anti-social.

This is the whole point of the Objectivist point of view.