Arranged for public viewing outside the Wadsworth Atheneum gallery in Hartford, the covers, 228 in all, are more than an unusual art exhibit. They are also a memorial to the thousands of Americans, most of them young men, cut down by the bullet. They have been moulded from iron melted down from 11,194 illegal guns collected by Connecticut's police since 1992.
Hand guns have become a big issue in Britain after Dunblane. But in the US, there are 72 million of the things at large, and firearms account for about 40,000 deaths a year.
Created by Maine artist Bradley McCallum and unveiled for public viewing this week, few projects have so vividly depicted the scale of America's firearms crisis. In this state alone, 320 young people have been killed by guns since 1988, many of them in Hartford.
There is an added poignancy to their presence. This city was the home of Sam Colt, who introduced the first revolving-chamber handgun, and who, just to the south of here, once operated the world's biggest firearms factory.
Next spring, the covers will be symbolically returned to the streets where today so many of the gun battles are fought. Some of the covers, which bear "SEWER" in large print around their outside, will be installed in the streets around the gallery.
Many others, however, will be placed around Hartford schools and in neighbourhoods where gun violence has been most prevalent.
Their origins, meanwhile, will be on display for all to see. Imprinted on each cover is the message: "Made from 172 lbs of your confiscated guns". In addition is the Latin motto of the Colt company: Vincit qui patitur and its two optional translations: "He who perseveres is victorious" and "He who suffers conquers".
In fact, the state of Connecticut has been sending guns confiscated by the police to a Massachusetts foundry where all of the state's manhole covers are made since 1992.
The practice was instituted by the former Connecticut governor, Lowell Weicker. Previously, guns collected by the police were sold at auction, which meant many of them finding their way back to the streets and to acts of crime.
"Hopefully, this project will serve as a catalyst for dialogue that will address how we can manage guns in a instructive way, " said McCallum, who has entitled his exhibit: The Manhole Cover Project: A Gun Legacy. He likens his work to the old adage of beating swords into ploughshares.
Viewers of the piles of covers can also listen at audio stations to testimonies from a collection of local teenagers who have either witnessed gun violence, been the victims of it, or shot someone themselves.
One voice is of young black man, who, with his mother, witnessed a close friend being gunned down while driving through a city neighbourhood in his car.
Minutes earlier, he had been with him in the car. "You know, it is always like that. I was just with him. People are always saying that. And you think that could have been you". He calls his a "lost generation" because of gun violence, and blames the police and the government. "They make 'em [guns] available to us".
Among those feeling the power of McCallum's exhibition is Inez Yoder, a retired visitor from California. "I think what he has done is just wonderful," she says.
"You look at these covers and you understand the weight of it all. And I mean that literally and figuratively".