Seventeen firearms were handed in at Aylesbury police station during a two-week amnesty by Thames Valley Police.
The Hand In The Gun campaign collected 255 weapons as it offered members of the public the chance to surrender firearms and ammunition without fear of being prosecuted for holding them without a licence.
Police also accepted 127 lots of ammunition and a pre-war training grenade which was passed on to trained bomb disposal officers.
Weapons handed in to front counters will now be forensically examined, with information sent to National Ballistics Intelligence Service (NABIS) where appropriate.
Chief inspector Lindsay James, who led the campaign, said: “We have been extremely pleased with the number of firearms and ammunition handed in and consider the surrender to have been a great success.
“I would like to thank the public for their excellent response.
“Every weapon handed in is now one less that could have ended up in the wrong hands, making the Thames Valley a safer place to live.”