Olsen, a 17-year-old from Cordova, Tenn., holds a three-shot lead over Wyndham Clark and Robby Shelton. Olsen is at 8-under-par with one round to go.
First-round leader Cody Proveaux of Leesville, S.C., shot 77 and is 1-under for the tournament. North Augusta's Matt NeSmith fired 3-under 69 and is at 2-under.
Augusta's Greyson Sigg improved to 74 today and is at 150 for the tournament.