Orbital period versus companion mass for diverging binary tracks from our simulated grids that have a similar NS spin as the observed huntsman source 1FGL J1417.7–440 (2.66 ms) within a 20% margin (dashed gray curves). The term M_c is the mass of the companion to the NS, and P_orb is the orbital period. We further show the binary that best matches the sources in its orbital evolution in blue curves, where β = 0.0, f_pulsar = 0.1, $M_{\mathrm{c}}^i=2.0{\mathrm{M}}_{\odot }$, $M_{\mathrm{NS}}^i=1.3{\mathrm{M}}_{\odot }$, and $P_{\mathrm{orb}}^i=2.6$ d.