Polarization-adjusted convolutional (PAC) codes have been demonstrated as a significant breakthrough close to the dispersion bound approximation. However, the above superiority is achieved in the context of a configuration of specific code rate thus far, which limits the flexibility in real use. Against this backdrop, this paper introduces a new code construction under the union upper bound (UUB) in accordance with the Hamming weight spectrum. What's more, we combine such construction with Reed-Muller (RM) design rule by efficiently selecting bit-channels on the basis of Hamming distance. Finally, we demonstrate the performance improvement compared to its conventional PAC counterparts.