  We consider right-handed neutrino pair production in generic $Z^\prime$
models. We propose a new, model-independent analysis using final states
containing a pair of same-sign muons. A key aspect of this analysis is the
reconstruction of the RH neutrino mass, which leads to a significantly improved
sensitivity. Within the $U(1)_{(B-L)_{3}}$ model, we find that at the HL-LHC it
will be possible to probe RH neutrino masses in the range $0.2\lesssim M_{N_R}
\lesssim 1.1\,$TeV.
