While I'm not a fan of assault weapons, the law was useless. There were tons of loopholes. For example, while the law banned magazines of over 10 rounds, plus certain types of weapons, it did not ban weapons or magazines manufactured prior to the date the law was passed. Thousands of these were on the market and remained fully legal. In fact, Glock and other manufacturers offered to even trade new models of weapons to police departments for their old, grandfathered in weapons, straight up, because the 10+ shot clips were so valuable. The law didn't stop criminals from getting assault weapons, only homeowners (not that I think most homeowners having an AK-47 is a good thing).
I think a better solution is requiring everyone who wishes to purchase a weapon in that category (this also goes for CCW or handgun permits) to have complete a course (and retake it every x number of years) that teaches them how to use said weapon safely without shooting their neighbor, their foot, etc. as well as best practices for securing the weapons in their own home so they won't be used against them, or found and discharged by their children.
Just my .02
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