The Lewis Gun utilized by British and American forces weighed 13 kg and could be carried by a single soldier. The French Chauchat was even lighter at nine kg. Although a lot less effective than heavy machine guns, these weapons gave the infantry a crucial source of cellular automatic fireplace. https://machguns.com/product/lot-1460-military-armament-corporation-m10a1-smg-silencer-class-iii-nfa/