Mayor James J. Fiorentini says more than 50 guns and hundreds of rounds of ammunition were turned in, including 30 working guns and about 50 Russian-made, armor-piercing bullets, during the city’s first gun buyback program, which was held last month. Most of the weapons were turned in by people who had guns left to them by a relative and feared that their homes would be broken into by someone seeking to steal the guns, the mayor said in a written statement. The buyback program also yielded one grenade that appeared to be live; the State Police took it for detonation. The program cost about $3,000. The guns collected will be melted down, Fiorentini said.