Jesus wouldn't run around with a sword, because he can walk on water. Ordinary men like David, however, were commanded by God to take up the sword and defend God's chosen People. I think we both believe in saving lives. We just have different ways to go about it. The preferable option is to run away. But if that doesn't work then I'd choose my life or the life of a family member over that of a murderer. And maybe your way suits your country for the time being. But I'm a little concerned when a powerful, warring nation starts taking an interest in disarming its citizens at the cost of freedom and lives.
Notice that the above mentions both freedom and security while supporting the right (not of the official military but of a citizen military - the militia) to own weapons (not just firearms but arms). I think if you're going to defend yourself and others the freedom to have the means to do so really helps. The above realizes that the life of a nation comes from its people and the people should therefore have the freedom to secure their interests.
My country (NI) isn't disarming its citizens at the cost of lives. Through disarming its citizens, it has reduced casualties, to a considerable degree.
I strongly disagree with the war in Iraq and Afghanistan (if that's what you are pointing out as being the war of this 'warring nation) as having ever been justified, thus I strongly believe that any consequences of such war are things that are simply cause and effect, and that America and the UK will have to deal with.
The US committed the most heinous international crime in invading Iraq and Afghanistan, by the laws of the Geneva convention, which my great-grandfather fought for in WW2. WW2 was a monstrosity, and these people fought for something worth fighting for. However, the UK entered this war, backing the US, and have contributed to this international crime, fighting a war with drones, jets, rockets, missiles and other weapons, against an unseen enemy of no particular nationality. A war in which more than 80% of the casualties are farmers and villagers, women and children.
If, however, you are referring to the 'Troubles', as what makes this country a 'warring nation', then I would like to inform you that they are officially over.
The point of the matter is, yes, the law affords you the right to freedom, and to a gun, and to the means to kill, should you wish to, but as followers of Jesus, if we are to truly emulate him, then we would not strike our enemies.
In saying that, I would find it morally conflicting not to protect my innocent child. I have empathy for the perceived need for guns in this respect. But I can tell you, that since the banning of guns, few, very few people here have needed such a means of defense.
Generally, people who enter your home won't be there to murder your children, only to steal your laptop and TV. Of course, there are exceptions, and I see the value in the point you make.
I suppose it is a matter of personal decisions. Personally, I feel that banning guns here has done far more good than harm.