Paul Tucker demonstrates weapon parts that can easily be obtained through the mail. Tucker’s on a mission to keep the weapons out of the hands of terrorists. Brooks Sample/DFWCN photo Paul Tucker is not the kind of man who most people would expect to be involved in gun control. He's a Marine Corps veteran of Vietnam, member of the National Rifle Association, hunter, and avid gun collector. "I'm for the Second Amendment," the 57-year-old medical software developer and consultant said as he displayed World War II-era British Enfield rifles at his Collin County home. But the terrorism threat looming...