The M60 itself weighs about 23 lbs... as for the ammo box, I can't tell you how much that'll weigh, as it'll be dependent on the dimension, what padding there is in it, what material it's made from.
Ammo weigh's 100 pounds
It depends on the kind of ammo. A bomb can weight tons of tons of metric tons. A .50 caliber bullet can weigh around a pound.
3-4 lbs
About 7.5 ounces, depending on which bullet is used.
20kg
Can't be answered without knowing the exact load.
Depends on the specific model/caliber.
The MG42 Machine guncould either held a 50 or a 250 round belt.
35 lbs. (15.9kg) 100 rds empty can wt. 5.3 lbs
I think there are 200 bullets in a uzi ammo clip
The weight of a fully loaded magazine with 5.56 ammo can vary based on the size and material of the magazine. However, typically a fully loaded 30-round magazine with 5.56 ammo can weigh around 1 to 1.5 pounds.
It depends on what kind of ammo.