The strongly worded announcement from the nationwide store chain came as students at Marjory Stoneman Douglas High School in Parkland, Florida, returned to class for the first time since a teenager killed 17 students and educators with an AR-15 rifle two weeks ago.

"When we saw what the kids were going through and the grief of the parents and the kids who were killed in Parkland, we felt we needed to do something," Chairman and CEO Ed Stack said on ABC's "Good Morning America."

The change in sales practices, and the emphatic words from Stack, put Dick's out front in the falling-out between corporate America and the gun lobby. Several major corporations, including MetLife, Hertz and Delta Air Lines, have cut ties with the NRA since the Florida tragedy, but until now, none were retailers that sold guns.