What is the test for a charge of possession of cocaine base for personal use and not for sale?

Appellant first argues that the district court should have excluded some of the cocaine base from the amount it used to determine his base offense level because it was for personal use and not for sale. While there was evidence that some of the base could have been for personal use, defendant has utterly failed to carry his burden of showing the district court's contrary finding--that all the drugs were possessed by defendant as part of a common scheme--was clearly erroneous. See United States v. Turner, 898 F.2d 705, 710-11, (9th Cir.), cert. denied, 110 S.Ct. 2574 (1990).