A Heckler and Koch SL6 or SL7, not sure which. See also TDF 62.
SL7: "The Heckler & Koch SL7 is a roller-delayed blowback operated sporting carbine made by Heckler & Koch. It was chambered in 7.62×51mm NATO caliber..."
Developed in the 1980s, one of the niche markets it appealed to in the U.S. was as a "quasi-military" rifle for low-key law enforcement. They never really took off, though, and was later replaced by the company with the more sporterized SLB 2000:
TDF INDEX: Cats, Guns, and National Security: THE DAILY FUDD index. https://catsgunsandnationalsecurity.blogspot.com/2021/03/the-daily-fudd-index.html