We have developed an atom-guiding technique that loads
3×106 cold rubidium atoms into hollow-core optical fibre, an order-of-magnitude larger than previously reported results. This achievement was guided by a physically realistic simulation that led to an experimental loading efficiency of
3%, giving a peak optical depth of over
600. The loading efficiency was limited only by the geometric overlap of the atom cloud an an optical guide beam, and we have identified techniques that would allows us to exceed this limit. We also present a fast and minimally destructive probing technique that enables us to follow the dynamics of the cold atom cloud as it falls into the fibre - this strengthens the confidence in our detailed model, and enables adjustment of the experiment into an optimal state. We are able to observe the effect of light-assisted cold atom collisions as well as background gas collisions in the fibre. The combination of these observations and physical understanding from the simulation allows us to estimate the ultimate limits to loading cold atoms into hollow-core fibres.