So getting rid of the unused gun in the attic for a few hundred or thousand dollars may well be a simple and cheap technique to reduce suicides.
How many suicide deaths would happen with fewer firearms available? I suspect a large portion of the suicide victims may not even be the owner/purchaser of the firearm used. Among all the methods, suicide by firearm is awful because it's so effective. Without an available firearm, attempting suicide by another method might be something that could be recoverable with some intervention after the attempt. Seems like a buyback could reduce the opportunity for deaths and injuries due to suicide attempts.
If people want to suicide, they'll suicide.
> Seems like a buyback could reduce the opportunity for deaths and injuries due to suicide attempts.
Attempting to reduce deaths will only increase permanent injuries. That will certainly be a burden on the medical system which comes as an added expense on the willfully living. If people want to kill themselves in the least painful and most effective way they can afford, they shouldn't be prevented. It's tortuous to deny a person the right to dispose of his own life as he sees fit by means of his own property.