What is the test for a defendant to argue that his sentence was improperly calculated as a result of his possession of methamphetamine as opposed to l-meth?

Tuck contends that: (1) his sentence was improperly calculated because the government failed to prove that the substance he possessed was d-methamphetamine as opposed to l-methamphetamine and (2) that his trial counsel was ineffective for failing to raise the issue at sentencing. These contentions are foreclosed by United States v. McMullen, 98 F.3d 1155, 1157-58 (9th Cir.1996) (holding that defendants cannot raise d-meth/l-meth claim for the first time in a section 2255 motion and concluding that trial counsel's failure to pursue the issue at sentencing did not fall below an objective standard of reasonableness). ¹