After retiring from playing, Berry joined Tom Landry's Dallas Cowboys coaching staff as receivers coach. In 1970, after two seasons, Berry took a job with Frank Broyles at the University of Arkansas as receivers coach. In 1973 Berry joined Don McCafferty with the Detroit Lions as his receivers coach. In 1976, Berry joined former SMU teammate Forrest Gregg as his receivers coach with the Cleveland Browns. Berry joined the New England Patriots as receivers coach under Chuck Fairbanks in 1978. He stayed on with new coach Ron Erhardt until Erhardt and his entire staff were fired following a 2-14 1981 season. Berry left football and worked in real estate in Medfield, Massachusetts, until the Patriots fired Ron Meyer in the middle of the 1984 season and hired Berry to replace him. Under his leadership, the Patriots won four of their last eight games and finished the season with a 9-7 record. Berry's importance to the team was reflected less in his initial win-loss record than in the respect he immediately earned in the locker room - according to running back Tony Collins, "Raymond Berry earned more respect in one day than Ron Meyer earned in three years".  In the 1985 season, the team improved further, posting an 11-5 record and making the playoffs as a wild card team. They went on to become the first team in NFL history to advance to the Super Bowl by winning three playoff games on the road, defeating the New York Jets 26-14, the Los Angeles Raiders 27-20, and the Miami Dolphins 31-14. It was the first time the Patriots had beaten the Dolphins at the Orange Bowl (Miami's then-home stadium) since 1966, Miami's first season as a franchise. The Patriots had lost to the Dolphins there 18 consecutive times, including a 30-27 loss in Week 15 of the regular season. Despite their success in the playoffs, the Patriots were heavy underdogs to the Chicago Bears in Super Bowl XX. They lost 46-10 in what was at the time the most lopsided defeat in Super Bowl history. "We couldn't protect the quarterback, and that was my fault. I couldn't come up with a system to handle the Bears' pass rush", Berry acknowledged.  The following season, Berry's Patriots again recorded an 11-5 record and made the playoffs, but this time lost in the first round of the postseason. That was the final time the Patriots made the playoffs with Berry as their coach. They narrowly missed the playoffs with an 8-7 record in 1987 (a strike-shortened season) and a 9-7 record in 1988. Then in Berry's last year as a coach, the Patriots finished the 1989 season 5-11. New Patriots team owner Victor Kiam demanded Berry relinquish control over personnel and reorganize his staff; Berry refused and was fired. His regular season coaching record was 48-39 (.552) and he was 3-2 (.600) in the playoffs.  After a year out of coaching, Berry joined Wayne Fontes' staff with the Detroit Lions in 1991 as their quarterbacks coach, and then held the same position the following season on Dan Reeves' staff with the Denver Broncos. Reeves was fired after that season, along with his entire coaching staff.

Answer this question "How long did he stayed with Don McCafferty ?" by extracting the answer from the text above.
In 1976, Berry joined former SMU teammate Forrest Gregg