The plea was delivered by their attorney, Colin Campbell, during his final address to Lord Cullen's inquiry which closed this week.
Now was not a time to "tinker" with the laws, said Mr Campbell. It was of crucial significance that, as at Hungerford, the Dunblane killings were carried out with a legally-held weapon, and the death toll could have been hundreds if Thomas Hamilton had arrived when the hall was full.
Central Police's "incompetence" in rooting out Hamilton was partly to blame, but all licensing systems were flawed, and, without a ban, another Dunblane could happen. The machete attack at St Luke's primary in Wolverhampton this week had strengthened the urgency of the families' plea, said Mr Campbell.
Iain Bonomy, QC for the Crown, said: "The inquiry must never lose sight of the enormity of what Hamilton did. The picture we must have of those little shattered bodies - these are the matters that brought us here." He said any recommendations on school security would depend on finance, but councils may have to accept responsibility for the "accreditation they coincidentally give" to organisations using school premises.
Solicitor James Taylor defended the police and said it was "grossly unfair" to blame them for the tragedy.
Grieving Dunblane parents this week relived their anguish in the wake of the Wolverhampton stabbings. Breaking their silence for the first time since the Dunblane massacre, they asserted that if firearms instead of a machete had been used at St Luke's school, on Monday, "we would be talking about deaths instead of injuries".
The Dunblane group - an injured teacher and the parents of five dead children and one injured child - claimed Wolverhampton proved that while there were evil people in the world, access to legally-held guns was an unacceptable risk for society to take. More than 700,000 people who signed the parents' Snowdrop petition agreed.
John Crozier, whose daughter Emma, five, was murdered by Hamilton, said: "Our children paid the price of society's need to be able to target shoot. My daughter's right to live is more important than anyone's right to shoot a gun."
Pamela Ross, who lost daughter Joanna, five, at Dunblane, said: "Each day we live with the loss we have suffered. Nothing in the future will ever allow us to feel our lives are complete. There will never be a point at which we can say we are coping and everything is fine, because it will never be."