The experience elsewhere offers little hope that the program will make a noticeable difference. After a successful 1974 buyback in Baltimore, the firearm homicide rate jumped by 50 percent. A study of a Seattle effort found it "failed to reduce significantly the frequency of firearms injuries, deaths or crimes."
This is the pattern wherever turn-ins take place. A 2004 study by the National Academy of Sciences concluded that "the theory underlying gun buybacks is badly flawed and the empirical evidence demonstrates the ineffectiveness of these programs."
The people who participate are generally those who are least dangerous. Those who are most dangerous have no motive to participate. So when the buyback is done, the number of armed criminals will most likely be unchanged.
Advocates may think that getting rid of weapons will at least prevent accidents and suicides. But some people who hand over a gun will hang on to other guns, which they are just as likely to handle carelessly or leave where a child can find it.
As for suicide, the odd thing about people intent on killing themselves is that if a firearm is not available, they can find plenty of other methods that will serve their purpose. The National Academy study said that "gun control policies may reduce the number of gun suicides, but they have not yet been shown to reduce the overall risk of suicide in any population" (my emphasis).
This year's turn-in will no doubt garner a decent haul of weapons. But for anyone anticipating a drop in gun violence, it will mostly yield disappointment.