  Experimental conductance histograms built from several thousand successive
breakings of sodium nanowires exhibit peaks up to rather high conductance
values (100 x 2e^2/h). In this paper, we present results from a disordered
free-electron model of a metallic nanowire, which was previously successful in
describing both conductance histograms and shot noise measurements in gold
nanocontacts with much lower conductances. We find in particular that, with a
modification of the model of disorder, the conductance histogram can be
understood as an interplay of conductance quantization and disorder for low
conductances (G < 10 x 2e^2/h), while peaks corresponding to higher conductance
are actually a combination of several ``quantized conductance peaks''. We also
predict a saturation of the shot noise at high conductance to about 1/10 of its
classical value 2eI.
