this guy has the best "mad minute" i have seen video'd
i think if he kept it at the shoulder while reloading he'd save time. shooting standing with a rest (as from a trench as stated in one of the articles) would also help.
this is all conjecture on my part though as i have yet to get my smle and drill rounds to practice/experiment with this.
edit: another thought, from playing with mk4 chargers it seems that the area that causes the most holdup's in smooth stripping from the clip is the holes in the bottom catching the rim of the round. the mk2 chargers (as the guys setting the records would have had) might be better in this department but i don't have any to experiment with.