The post above shows it all. One could elaborate, but it is thought out and said to a degree where there is really no need.
It comes down to this, someone can buy an AK-47 fully automatic in downtown London for the going price of $800 - way cheaper than it is here to buy one fully automatic. The point being, in a perfect world, one would not need guns. Problem is, you live in an imperfect world. You do the math.
-S
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