The Town Council heard several hours of public comment before voting 4 to 3 to change the 10 year old law.
Mayor Paul Donahue voted with the majority.
He said people can currently, openly carry "machetes, swords and chain saws" into public buildings and parks, and those things can hurt people, "but people don't do it."
He says the earlier ban was reasonable, but not necessary, because even though people can openly carry a gun in this state without a permit, the vast majority don’t.
"How many people have you ever seen open carrying in Colorado, whether it’s public buildings or parks or wherever, you just don’t see it," Donahue said.
Donahue feels it’s important to protect the constitutional rights of people who want to be able to carry guns.
A survey of Castle Rock police officers indicated most wanted the ban to stay in place.