The 5f spectral weight in the heavy-fermion materials UAl2 and UPt3 has been measured by electron spectroscopy, and compared to that in density-functional calculations. The one-electron 5f widths are both too large to account for the enhanced values of the specific-heat coefficient, and too small to account for the measured widths. In the Anderson Hamiltonian, both discrepancies arise from the 5f Coulomb interaction. It is pointed out that an enhanced value does not imply enhanced magnitude of the 5f spectral weight at EF. © 1985 The American Physical Society.