500,000,000 weapons - a whopping 0.028% of which are used in some type of crime. That leave 99.972% of that 500 million never used for criminal activity.
Let me explain - I have x number of weapons in my home right now - not one of which is registered - why? Because I don't have to. I'm not alone - there are tens of millions of gun owners just like me. How does the Government know what I do and do not have? There is no way for them to know.
What if someone changes their barrel?
In addition, it has been suggested and roundly defeated for reasons already cited. But your post bring something else up I would like to ask about.
According to the ATF
Between 9.9 million and 13 million weapons are manufactured each year.
Picture what would be needed to build a database that would house 500,000,000 current weapons and 9-13 million additional weapons a year that would actively track them from manufacturer to subsequent owners - giving access to 3,142 counties and innumerable police departments.
While it is not a bad idea - I doubt if it is even partially obtainable from the start.
Somehow I doubt that.
But thanks - It is an interesting point.