"I'm not a 'sports' type guy but I will definitely be going to @Dicks," Jeff Rodenkirch wrote.
As some call for a boycott of Walmart, Dick's Sporting Goods — which stopped selling guns and ammunition in 135 stores — has seen a 3.2 percent rise in profits this year.
The NRA linked to a website blaming law enforcement for the Parkland shooting.
"He was really just trying to buy a rifle."
"Thoughts and prayers are not enough. We have to help solve the problem that's in front of us."