Let's put Luke 22:16 into perspective. Jesus warns the Apostles about the coming tribulation with his arrest. Peter misunderstands the symbolic use of the "sword" (remember Paul's admonition to put on the armor - with sword and shield- of faith) and says he has two swords. In the garden, Peter cuts off the servants ear. Christ rebukes him and heals the servant. Later on Peter denies Christ three times. That's the happy ending for using a weapon to defend one's self. The evil was not the men coming for Christ but Satan "sifting them as wheat".
Now, someone breaks into my house and has a gun. I am to remember that using and possessing a gun is stupid, as I said it is. I will indeed remember that and I will trust in Christ. What greater weapon is there? Peter, when sinking on the water (after first walking on it) as his faith weakened cried out, "Lord save me" - and he did.
With a gun I could pray, "Oh Lord, my faith is in you but I can't trust you to help me right now so I pulled out the Holy Hand-grenade of Antioch. This is what I trust in at the moment 'cause if I wait for you to do something I and my family will surely die (which of course would only bring us into heaven and into your presence) but instead of that I'm going to shoot this son of a bitch so he can stand before you. Of course Lord, I don't know what circumstances lead to this moment of confrontation and what I should learn from it, but Dear Lord I have spent money on a gun and I'm going to use it. I will follow the honored American tradition of "kill them all and let God sort them out". Dear Lord, make my aim true as I kill this guy 'cause you Dear Lord can't do anything else to help us but somehow I think you can make the bullet fly straight as I stand here in an adrenaline rush and hand shaking."
That's quite a prayer. The one ending "And lead us not into temptation, but deliver us from evil. Amen." is pretty good.
I don't buy this hand gun crap at all.