You may have heard this argument before, that guns are tools. They serve a purpose, just like a hammer or a drill.

Yes, but they are tools of death, they were designed to kill and their only purpose it to kill. They serve no other need.

Perhaps. In fact, I shall say that this statement is very true of assault rifles and machine guns. They were designed to take life with the greatest potential efficiency. They can, however, be quite fun to use, even just blatting rounds into an empty field can be fun, but this is incidental. They were designed for killing, so you are going to say that their possible purpose of "fun" is irrelevant. Okay, remember that.

Let's move on to hunting rifles. Yes, their purpose is "death", but not of people, but of game. Their role is to provide food. This role may be somewhat negligible in this day and age, but it's what they're designed for, right? So shouldn't their possible violent use be considered irrelevant?

Now what about target rifles? I have seen and held in my hands a target rifle worth more than I earn in a year (which admittedly is piteously little, but the point still stands). Thousands of pounds worth of "tool", designed to punch holes in targets, and who's engineers would never have dreamed of it being used to take life. It's purpose was sport shooting. Yet nothing is stopping someone killing someone else with it, anymore than we are stopping someone beating someone else to death with a phone book.

If we say that the primary use of the assault rifle is death, then shouldn't we also see that the primary use of other types of firearms is merely sport?

I am, at least in part, playing the devils advocate here, however if you are to make the argument that "guns are designed for killing", you should really be made aware that that isn't necessarily true.