GREAT idea - but would that be legal for you to do? I guess a private sale requires no paperwork? (I assume this would be considered a 'sale' )

Didn't the government did that for years? At times weapons identified as "buyback" by serial number ended up south of the border being used in crimes. Government and police couldn't explain how that was possible.
Arizona[edit]
Gun buybacks have been held in Tucson (one in 2013) and Phoenix (three in 2013).

In 2013, House Bill 2455 was signed into law by Governor Jan Brewer. H.B. 2455 and Arizona Revised Statute 12-945 were enacted after lobbying by the National Rifle Association and other organizations and require that firearms seized by, surrendered to or acquired by law enforcement or other government agencies may not be destroyed. Firearms acquired through programs such as gun buybacks or seized in the course of a criminal investigation that are legal for private citizens to possess must be disposed of by sale to a federal firearms licensed dealer. These statutes have raised controversy, with opponents charging that the statutes will turn gun buybacks into recycling programs. Proponents of the measures point out that firearms purchased through private buyback programs may be destroyed.[10]

California[edit]
On December 15, 2012, the day after the Sandy Hook Elementary School shooting in Newtown, Connecticut, an anonymous donor funded gun buyback events in Oakland and San Francisco, California. Hundreds of area residents received $200 cash for each firearm sold, "no questions asked." The guns were to be destroyed.[11] A mile-long line of cars lined up into the East Oakland church parking lot that served as that community's exchange location, prompting the private donor to double his contribution.[11]

Over 600 guns were bought between the two locations. One week later, it was learned that the event was largely funded by a medical marijuana dispensary, whose executive director said, "It's part of the philosophy we practice called capitalism with a conscience."[12]

There was a buyback program in Los Angeles that offered prepaid credit and grocery cards in exchange for guns.[13]

Maryland[edit]
For two months in 1974, the Baltimore Police Department ran what is believed to have been the first gun buyback program in the U.S. Police commissioner Donald Pomerleau, not known as an advocate for strict gun control, reportedly came up with the idea while at a funeral for an officer who was shot in the line of duty. Operation PASS (People Against Senseless Shootings) paid a $50 "bounty" for surrendered guns and $100 for tips leading to the confiscation of illegal guns. Some bounty seekers attempted to game the system by buying cheap, new guns that retailed for $21.95 and then trying to turn them in. In all, the police collected 13,500 of firearms - mostly handguns - at a cost of over $660,000. However, the city's already high gun homicide and assault rates actually increased during the program, for which police officials offered no explanation.[8]

Massachusetts[edit]
From July 12–14, 2006, the Boston Police Department, with support from dozens of community and faith-based organizations, collected 1,000 firearms. Residents received $200 Target gift cards in exchange for their guns.[14]

Michigan[edit]
At an August 2012 buyback, the Detroit Police Department paid $16,820 for 365 guns, including six assault weapons and a few sawed-off shotguns. The guns were accepted "no questions asked" at a church where members had collected $18,000 to help get dangerous weapons off the street. People could receive from $50 to $100 for unloaded, operational weapons. Gun-carrying protesters offered those in line more money not to turn in their firearms.[15]

New Jersey[edit]
A buyback in Camden, New Jersey, in December 2012 collected 1,137 firearms.[16] In April 2013, Newark Police Department collected more than 200 firearms during a buyback funded by Jewelry for a Cause.[17] This was the first buyback in the city's history to be completely funded through private sources.[18] Such programs allow residents to turn in guns for cash.[19] In January 2014, Newark police director Samuel DeMaio said he was reviewing the implementation of an ongoing program instead of once or twice a year. Gun buybacks in several locations in Essex County, New Jersey, including Newark, collected about 1,700 guns in February 2013.[20]

Washington[edit]
The city of Seattle has experimented with Gun Buy Back Programs since the early 1990s.[21] Seattle's 1992 gun buyback was initiated in response to a string of shootings in a local neighborhood. The buyback program was watched with great interest given the local demographic and the generally positive public support for the buyback from residents of Seattle and the surrounding area. A public health survey titled "Money for Guns" was conducted and while it concluded that no statistically significant result was produced on Seattle's gun crime or gun death ratio, the report maintained that a larger buyback program would be sure to yield positive results.[22] Over 20 years later Seattle would again make headline for its bold gun buyback program in 2013, but perhaps not for the reasons the programs sponsors and organizers would have liked. While the program, could be considered a success, collecting more than 700 guns, handing out almost $70,000 in gift cards and even netting a Stinger missile launcher tube (minus the missile),[23] the program also had a widely unanticipated effect from the local gun buying community. Hundreds of gun buyers showed up to the event seeking to offer cash for valuable antiques or functioning second hand firearms. The lack of any need for background check in transactions involving private firearms sales turned the city sponsored event into an open air gun bazaar.[24] Since then Seattle has not suffered alone in its gun buyback program woes, with other cities experiencing similar problems, whether it be private sales or local gun owners taking advantage of lucrative gift card offers to unload rusted or non-functioning firearms onto the police.[25]

Maybe that is what will take a grassroots movement...