The RCM has potential to be a smooth feeder. Belted mags--gun scribe rantings aside, typically feed very smoothly. Crud, my M-70 375 H&H will feed and chamber empty cases. A belted mag is nominally .532 at the rim and the belt.
The WSMs have had their share of feeding issues. They have a nominal .550 head diameter.
The RCM has a head diameter of a belted mag. Since the belted mags feed well, an RCM would seem to have a good chance of feeding well too.
