That's why Sam was told not to carry it. She travels extremely light anyways. All she has throughout the main game is a hunting rifle, handgun, the toy she reclaimed after the death of the black brothers, and the picture of Joel and Sarah. Joel is the carrier of illogical weight. He carries the pendants, notes, comics, 2 revolvers, two shotguns, a handgun, a rifle, bow, smoke bombs, explosive cans, molotovs, medical supplies supplement pills, scrap metal, rags, alcohol, blades, sugar, explosive compounds , binders, weapons suitable for hand to hand combat including two by fours, machetes , bats, and pipes, shivs, all the ammo, and a military grade assault rifle at the very end. She carries a bit more in left behind, since you take control of her. She adds the large shotgun, crafting materials, a few notes, and crafted items On a side note, holding a can with homemade explosives and scissor blades jutting out is totally fine.