SAN ANTONIO — Angela L. Pena brought her family to the Alamo on Saturday. She also brought her black assault rifle, a .223-caliber LWRC M4, and had it strapped across her back. Her daughter brought her M&P rifle; her son-in-law carried his .308-caliber Remington R-25; and her 8-year-old grandson, Sebastian Gonzalez, had his Ruger 10/22 rifle.

“A rifle on our back is part of our everyday life, just like a cellphone is part of our everyday life,” said Ms. Pena, 48, who manages her husband’s dental practice in South Texas.

Here in the heart of the seventh-largest city in the country on Saturday, hundreds of gun owners like Ms. Pena and her family carried their firearms in the open outside the entrance to the Alamo as part of a gun rights rally that was peaceful but loud.

For tourists, it was a startling sight: men, women and children openly carrying loaded and unloaded shotguns, hunting rifles, AR-15s and AK-47s as if they were purses or backpacks. A young man in jeans ate a breakfast sandwich with his assault rifle resting behind his back. A rally speaker with his own assault rifle confronted and quizzed police officials about their views of the Second Amendment, and the officials calmly looked on.