If you noted, that part of the Catechism addresses international arms sales to
nations, not the indivudual right to own firearms (unless I read Cardinal Dolan restricting “assault weapons” to the US Military), ie, “They see it as the most effective means of ensuring peace among nations”
Here’s a portion of the Catechism we’ve previously posted:
vatican.va/archive/ccc_css/archive/catechism/p3s2c2a5.htm
As a father, former member of the military, and as all able body are part of the state militia , I have a duty to defend my family and others. The US Constitution gives us “Legitimately (held) authority” to bear arms.