The Rangers were facing a team making a late-season playoff bid and Buffalo could have moved within two points of the final post-season spot with a victory.
New York, however, emphatically ended that hope by scoring the game's first six goals. The loss ended Buffalo's three-game winning streak and eliminated the Sabres from playoff contention.
The Rangers reached 50 points for the season and moved two in front of Winnipeg in the battle for the No. 8 seed. They are now one point behind the New York Islanders for the seventh position.
Richards scored a goal in each period and along with Carl Hagelin and Ryane Clowe produced a sudden surge that stunned the Sabres late in the opening stanza.
Those three players scored in a span of 1:14 with Clowe's goal coming just 4 seconds from the end of the period.
Richards scored 1:40 into the second period and completed his hat trick midway through the third.