It seems to me that the argument against restrictions comes down to two things:

1. Paranoia - it's a slippery slope that will end when all the guns are taken away, plus people who want more regulations will lead us down the same road that the Nazis led the Jews.

2. Don't take away my fun - it's fun to shoot up stuff.

I would never, ever want to take away someone's right to defend themselves and their property or to hunt for food and/or pleasure. However, there are certain weapons which were developed for use by the military. Their only reason for existence is to wipe out as many human beings as possible in as short a timeframe as possible. Those weapons should not be allowed in civilian hands - be it the actual weapons or high-capacity magazines, for example.

These same arguments can be made over and over and over and over. Nobody is going to listen if their minds are made up, not on either side.