Well, here's a statistic that many aren't aware of, but Lott does mention it. And it's a particularly compelling point when speaking to people who cite "other countries, like the UK".
Immediately after the last big gun ban in the UK, in 1998, FIREARMS violence DOUBLED... and stayed way up for 8 years. This is according to UK's own government statistics.
After that, it did start to decline... but at the same rate it was declining in other countries like the US, where gun ownership was going steadily up. So there is no valid argument that lack of guns caused the later decline.
I've argued before about this with people from the UK, who didn't seem to know about these statistics... and who suddenly shut up when they were pointed out. (I'd find a link but I'm too busy right now.)