The nationwide vote Sunday pits critics of Switzerland's high rate of firearms suicides against those who fear tighter rules may hurt the country's beloved village shooting clubs or cripple its citizen militia.
Doctors, churches and women's groups want ex-soldiers to store their military-issued firearms in secure army depots. The move would abruptly end a Swiss tradition still cherished by many men of keeping a rifle at home even after they have completed active military service.
"If you make firearms less accessible there will be fewer suicides. It's that simple," says Elsa Kurz of the Geneva-based organization, Stop Suicide. The group is one of dozens arguing that the easy availability of guns - some 2.3 million mostly military weapons in a country of less than 8 million people - is the reason why Switzerland has the highest rate of firearms suicides in Europe.
Backers of the new law also want the Swiss government to establish a national gun registry and ban the sale of fully automatic weapons and pump action rifles. That, they say, would help prevent the kind of devastating rampage seen in 2001, when 14 people were shot dead at a city meeting in Zug. Friedrich Leibacher, who killed himself after the massacre, used a commercial version of the Swiss army's SG 550 assault rifle - a gun still commonly found throughout the country in cupboards or under beds.
Those favoring stricter laws have produced posters with teddy bears oozing blood below the slogan "Protect families" and TV ads allegedly showing the aftermath of family massacres. Right-wing posters have featured muscular cartoon criminals threatening the nation's law-abiding citizens.
The proposal faces stiff resistance from gun enthusiasts in this small Alpine nation, where the right to bear arms is firmly linked to the national myth of William Tell - he of apple and crossbow fame - and to Swiss pluck against the Nazis during World War II.
In Bueren an der Aare, a small town in the western Swiss heartland, the local shooting club is, well, up in arms.
"They are taking the guns away from those who have been trained to defend Switzerland and not from the criminals," says Erich Sutter, a 58-year-old software engineer who volunteers evenings as a shooting instructor.
Like most men in Switzerland, Sutter was conscripted into the army as a young man, completing basic military service and later returning several weeks each year for refresher courses to keep the nation's militia ever-ready for possible invasion by hostile neighbors.
While air-powered sports weapons aren't directly affected by the proposed law, most gun clubs depend on soldiers who use their army rifles for target practice and hobby shooters who prefer using live ammunition. Without them, some clubs could be forced to close, says Sutter.
His views are echoed by Switzerland's sport shooting association, which represents some 3,000 local gun clubs.
"In our democracy, the clubs are a very important pillar of the community," says the group's president, Dora Andres, a fifty-something woman who keeps an assault rifle at home. "If you don't have clubs, where are you going to meet and talk to people? On Facebook?"
Another vocal minority claims that Switzerland's unique system of popular rule - expressed in endless referendums and a weak federal government - is in danger with this vote.
"The real purpose of this initiative is to weaken the militia army and withdraw the state's confidence in its citizens," says Markus Mueller, spokesman for a group of former and current senior Swiss military officers.
Mueller calls the proposal a left-wing conspiracy to weaken Swiss democracy. "Only a disarmed people can be oppressed. That's why we're against this," he told The Associated Press.
In fact, support for the new law comes from all parts of the political spectrum.
Daniel Wyss of the centrist Christian People's Party says there's no valid reason to keep assault rifles at home anymore.
"If you have a weapon in the house it increases the chances people will use them to commit suicides or murders in the heat of the moment," he says.
About a quarter of Switzerland's 1,300 suicides each year involved a gun, according to federal statistics. The exact number of military-issued weapons involved is disputed, but those calling for tighter rules claim they account for between 100 and 200 suicides a year, mostly among men.
Advocates for the new law also note that since Switzerland cut the size of its army in 2004, the number of firearms suicides among men aged 30-40 has been cut in half.
It is not known how many military-issued guns are involved in homicides each year, though Switzerland's gun murder rate is relatively low - just 24 in 2009, or about 0.3 firearms homicides per 100,000 inhabitants. By comparison, the U.S. rate in 2007 was 4.2 per 100,000 inhabitants.
Sunday's outcome is expected to hinge on the votes of women and young people.
A survey last month by the respected polling group gfs.bern found a narrow majority of 47 percent in favor of the proposal, with 45 percent opposed. About 8 percent of voters were undecided, according to a telephone poll of 1,209 voters.
The survey found 55 percent of women in favor, plus a majority of Swiss under 40. If both groups have a strong turn out, the measure is expected to pass.
"Our victory depends strongly on being able to mobilize women and young people," says Karin Jenni of Switzerland's Alliance for the Protection against Gun Violence.