Probably the best bet is to go visit a Target, ask to speak with a manager, and tell them, “I wish I could shop here, but with your anti-gun policy, I just don’t feel safe here. Goodbye.”
Happening just once, it would be an oddity that would be ignored. But if it happened at several different stores, it would eventually get the ear of their district managers. They are ambitious types, and want to get noticed by upper management, so are very interested in public feedback.
People did that at JCP and many got an earful back from angry managers, who defended their gay advertisements.
I won’t go to Target. I cannot believe any sane person would think a ‘gun free zone’ sign isn’t an aphrodisiac to armed criminals and basically invites them to attack their unarmed customers.
If I was a Target customer and got held up my a gun toting criminal, I would sue for the entire value of Target. And after winning, I would change the logo to a bullet and all employees would wear sidearms.