  We investigate real-space localization in the few-particle regime of the XXZ
spin-$1/2$ chain with a random magnetic field. Our investigation focuses on the
time evolution of the spatial variance of non-equilibrium densities, as
resulting for a specific class of initial states, namely, pure product states
of densely packed particles. Varying the strength of both particle-particle
interactions and disorder, we numerically calculate the long-time evolution of
the spatial variance $\sigma(t)$. For the two-particle case, the saturation of
this variance yields an increased but finite localization length, with a
parameter scaling different to known results for bosons. We find that this
interaction-induced increase is the stronger the more particles are taken into
account in the initial condition. We further find that our non-equilibrium
dynamics are clearly inconsistent with normal diffusion and instead point to
subdiffusive dynamics with $\sigma(t) \propto t^{1/4}$.
