This thread is still going? Since carrying a gun is just like carrying a sword around, what the OP is really asking is: would Jesus use a gun against a human. In my opinion, probably not. Of all the things He could do to defend himself, He probably would not resort to human weaponry. The Bible teaches us that most of the time Jesus relied on his wits when someone confronted him. The truth is, He has the power to change the hearts of men long before they confront Him. Let us recall He is the alpha and omega, and the Trinity is an omnipotent entity.
Now, since this thread has evolved into 'should Christians use guns' and 'is it ok for Christians to kill another human'. The answer varies depending on the individuals morals. As Julianna pointed out, there are many Christians involved in the military and paramilitary world. If there weren't, this world would be A LOT more messed up than it is. In a perfect world we wouldn't need weapons, but this isn't a perfect world. There is a difference between killing and murder.
A gun is just a tool. If you sit in a room staring at a loaded gun all day, it's not going to miraculously launch a projectile at you. Such an event would require human intervention.
Maybe we should get rid of motor vehicles? I mean, that would end all of the high speed drunk driving incidents, right? /End sarcasm