It seems to me that an ounce of prevention is worth a pound of cure, and a firearm, if cruising outside the US, specificly where they are illegal, (EG Mexico, etc) is a ton of cure, and it may just be the source of more problems than it fixes.
James Baldwin has a decent article on dealing with Piracy, on sailnet as a matter of fact:
Basicly, a gun may help get you away from pirates, but it''s not guaranteed. there is a chance you could make it through mexican waters without a gun, but a greater one that you''ll be spending a few months or more in a mexican prison. Myself, I''ll take my chance with out the gun, and just make sure pirates know that I''m not an easy target, and they should just move on to someone else, or at least leave me alone. Dont need a gun to do that.
Basicly, what seperates my home from my boat, is that my home wont be floating through areas where guns are strictly illegal, and the local LEO belive that the only reason someone would have a gun is to Shoot THEM with it. That makes for a less than hospitibal welcome.
-- James (Not Baldwin