If you have to rely on waiting until the Point of Sale to stop the wrong people from obtaining firearms, you're deluded.
Apparently, that's the metric Paul Helmke uses to calculate success. Thanks Paul for validating my statement.
Notice how "blocked sales" are his metric of choice. Not a reduced crime rate, not lower shootings, but simply the number of times the cash register doesn't go 'ding'. It appears false negatives are also included in that number.
You know how to tell that you're on the right side of a debate? When you're not concerned with having all the data available, good and bad, because you know that even the statistical noise won't harm your argument.