A small point to keep in mind with las weapon ammo is that, short of recharging, there's no way to 'top up' a used charge pack. i.e. you go through a blazing combat and use up half the pack, slot in a fresh pack then later get into another scrap; you now have 2 half-charge las packs and no way to fill one from the other. On a long patrol or the like, this could well result in the squad still having plenty of ammo, but spread out across 4 or 5 20-30 shot mags.
R.I.P. Thunder Child, ?? - 1897.