Gun purchase programs are great for private gun buyers.
If the government offers to pay $250 per gun, private buyers stand outside the gun purchase location and pay $300 for the good ones.
Then, the government gets a pile of non-operational, rusted out, antique "guns" for $250 each.
That works well as a government program because Tyrone tax dollars end up effectively subsidizing private gun sales...kind of like you wanting plumber tax dollars to subsidize racial studies majors.
And, in blue cities, Tyrone tax dollars subsidize straw purchasers (they get to buy $800+ guns for $300 each), which means more guns on the streets, so more urbanites are killed, which means Tyrone can tell those urbanites they need to vote for his party to get guns off the streets...and the leftist-blood-politics cycle continues, and you kill people to maintain political control.
All this falls in the "what could possibly go wrong" category. But, you like to lie to your own party, so this works for you.
[I don't usually read your posts. Just happened to see you lying in your post header before I logged in. So, why did you put "voluntary" in quotes. Did you mean "involuntary?"]