Two-dimensional angular correlation distributions of positron annihilation radiation (2D ACAR) in copper are calculated taking into account the electron-positron many-body enhancement effects. They are compared with the experimental results of Berko et al. Two kinds of enhancement, namely a state-dependent enhancement and a character-dependent one, are considered. In each scheme two different enhancement factors are used for s,p-electrons and d-electrons. Although the agreements between the two enhanced theories and experiment are very good, the character-dependent enhancement scheme seems to be better than the state-dependent one.