This fully-working handgun was handed in at a police station as a two-week firearms amnesty got under way on Saturday.
The Mauser revolver, which police said was in full working order, was left anonymously at Leicester's Keyham Lane police station.
It was the first "live" weapon to be surrendered.
The amnesty allows people to hand in guns or ammunition without fear of prosecution for illegal possession of a weapon.
However, the revolver will be examined by experts to check if it has been used recently or can be linked to any crimes.
A force spokeswoman said: "Obviously, the public would not expect us to ignore the fact that some of the guns handed in may have been used in crime.
"The amnesty means that people handing weapons in can do so without fear of prosecution for their illegal possession.
"Each weapon is judged on its own merits."
Elsewhere over the weekend, seven bullets which date back to the Second World War were passed to officers at Beaumont Leys police station, while a replica shotgun was handed in at Syston police station.
Leicestershire Police has urged people to take the opportunity to rid themselves of firearms – real or replica – over the next two weeks.
Chief Inspector Chris Brown, who is overseeing the amnesty, said: "We are really pleased with the response we have had over the weekend and we hope it continues."
Chief Insp Brown said the force was continuing its efforts to educate young people about the consequences of involvement in armed crime or the use of imitation weapons.
He spoke as the force released statistics for a range of gun crimes in 2011, 2012 and from January to the end of June this year.
The number of people injured in firearms incidents was 24 in 2011, 22 in 2012 and nine in the first six months of this year.
The number of occasions when a firearm was used to threaten someone was 45 in 2011, 46 in 2012 and 19 in the first six months of this year.
Chief Insp Brown said: "As well as the educational work we have been doing, there has also been a lot of work going on for a number of years to target criminals who have access to firearms."
There has been one fatal shooting in Leicestershire in the past three years – 30-year-old Hayley Pointon, of Hinckley.
The mother-of-two died following an incident in Sunnydale Road, in the town on February 3. A number of people have been arrested and the investigation is continuing.
About 800 firearms, including sawn-off shotguns, pistols, antiques and imitation weapons were handed in during the force's most recent amnesty, which took place throughout April, 2003.
People are advised to ring their local police station before setting off in order to ensure it is open and for advice on the safe transportation of a firearm.
The main collection points are the following police stations: Loughborough, Hinckley, Syston, Market Harborough, Melton, Oakham, Braunstone, Coalville, city centre (Mansfield House), Keyham Lane, Spinney Hill Park, Beaumont Leys and Wigston.
Advice is also available by calling Leicestershire Police on 101.
