Well, the situation in Alphen aan den Rijn (The Netherlands) this weekend has already proven that the laws don't make that much difference.
Some guy walked trough a shopping mall with a fully automatic rifle, shooting several civilians - some died, some got critically wounded - before committing suicide.

There's no way to get a permit for automatic weapons here, and the permits for other firearms are very strict (i.e. only valid on a certified shooting range, and so forth).