Adam Peters of Belle Fourche pleaded guilty to robbing the Phillips 66 Speedy Mart in Spearfish at gunpoint in November of last year.
Peters pleaded guilty Friday morning to interference with commerce by robbery and use and brandishing of a firearm during the commission of a crime of violence.
According to the factual basis statement signed by Peters, he went into the store on November 22nd and pointed a handgun directly at the clerk and demanded money and ordered a customer to the floor at gunpoint as well.
He left with about $130 in cash.
Peters faces up to 20 years in prison on the robbery charge and a possible life sentence on the gun charge.
Two other defendants in the case, Matthew Wainman and David Jackson, Junior, are still facing the same charges.