What John said... There's two types of loads a Soldier carries. One is an "existance load", the other a "fighting load"... Units moving into the attack would carrying a fighting load, while those that are moving from one place to another, especially units being rotated out of the line, would be humpin' an existance load... Fighting loads range anywhere from a butt-pack to a giant, 100lb ruck with nothing in it but ammo and a coule days' rations...
However, units at the jump-off point wouldn't be carrying rucks (that's where they'll leave 'em), just a minimum fighting load of ammo and grenades... It sounds like you're doing a town that isn't cleared, so it's likely that the grunts wouldn't be humpin' rucks in your dio...