KKR, the big American investment company, has acquired a controlling interest in Academy Sports + Outdoors, a chain of 131 outdoor and general sporting goods stores in the southern part of the U.S. The chain’s sales grew last year by an estimated 12.5 percent to $2.7 billion, making it the sixth-largest sporting goods chain in the U.S., trailing Cabela’s. The change of ownership follows the death of the company’s founder, Arthur Gochman, seven months ago.