The accused gunman in the Washington Naval yard shooting was able to buy a shotgun with out-of-state identification because of the Firearms Owners' Protection Act, passed by Congress in 1986.
An attorney for the Virginia gun shop adds Aaron Alexis passed a federal background check before buying a shotgun and ammunition.
Army veteran, Zachary Howard, said, "This stuff's just going to keep happening, and clearly it is. Just look at history. It's been happening more and more and more and it's so upsetting. Why are you trying to take away people's defense?"
Howard is with a group participating in a nationwide rally to uphold the U.S. Constitution, including the Second Amendment.
Cherice Morgan, a rally participant, said, "I'm not going to go somewhere unprotected. It doesn't make sense anymore."
"You're allowed to openly carry rifles and shotguns. They can be loaded," said Justin Delosh, with "Open Carry Texas" and another group called "Come and Take it Austin."
"We, personally, do not carry ammunition in the chamber when we carry...We don't go around any federal buildings or schools," said Justin.
Justin and Zachary say they were exercising their rights by strolling downtown with their rifles on full display.
They stopped for coffee and as they passed some Austin police officers on the street, they didn't even get a second glance.
Still, not everyone they came across seemed comfortable with them toting rifles around with full magazines.
Justin said, "I'm hoping that the public sees that law abiding citizens with firearms are no threat to anybody."
They feel for those that lost their lives on the Navy yard and hope the law changes to allow more people to be armed while on military installations.
"It's not the gun's fault. Stop blaming the guns," said Zachary. "People that do stuff like that is just very, very saddening to me, which is why I'm going to carry more and more often, in order to stop something like that. If something happened like that, I'd put my life on the line for these random citizens."
Tuesday is Constitution Day and the kick off to Constitution Week.