No, the P320 XCompact features an optic cut designed to accept optics that use the Deltapoint Pro footprint. The SIG SAUER Romeo 3 MAX uses the C-More footprint and would not be compatible. You will be able to fit optics such as the Leupold Deltapoint Pro, Sig Romeo 1 Pro, Sig Romeo Zero Pro, Holosun SCS-320, Eotech EFLX, Holosun EPS and more.