[@AdvancedJ3lly]the comrade is there to carry the ammo. 

As for the encumbrance. This is why the athlete skill is given to heavies. They can make a roll each assignment to double their carrying potential amongn other things.

Plus grav chutes get ditched after landing anyway. They aren't much use in hive city tunnels. That saves 15kg

I also have 45 toughness. So my total carrying capacity is 45 in this instance. 

To save on weight I would also abandon my shotgun and ammo.