If you look at their overall homicide rate since then, its barely twitched. It was 1.6 per 100,000 the year of their mass shooting that lead to the ban. Last year it was 1.0 per 100,000. That's not a huge difference. Heck, our rate when down more than their's (from 7 per 100,000 in 1993 (before our assault weapon ban) to 3.5 in 2016). We got a 50% reduction. They only got 37.5%.
Now admittedly our number is firearm homicides while their's is total homicides. I'll see if I can find info on our total homicide rate.
Edit: Our total homicide rate in 1993 was 9.5 per 100,000, in 2016 it was 5.4 for a difference of 43%. Still better than their 37.5%