Police in Helsinki collected 463 firearms and more than one tonne of illegal fireworks and other explosives from the civilian population under a four-day amnesty last week.
Residents of the Finnish capital were told they could hand in unregistered weapons without being asked any questions and with no threat of prosecution during last week.
The firearms collected included 260 handguns, 57 shotguns, more than 100 rifles and three machineguns, spokeswoman Ms Paivi Kaasinen said.
Authorities also received more than one tonne of fireworks and 50 kilograms (110 pounds) of other explosives including nine kilograms of gun powder, three kilograms of TNT, nine hand grenades, two two-kilogram fire bombs, one 45 and six 50 millimeter grenades, and one cannon shell.
Police said most of items were "souvenirs" dating from World War II.
"Finland has been in war, so there are a lot of these war souvenirs laying around," Ms Kaasinen said.
She said the campaign was successful and police are considering a similar amnesty program sometime in the next few years.
AFP