What is a BAR?
BAR in WWII terminology stands for Browning Automatic Rifle. The official designator was M1918A1. It was a .30 caliber fully or semi-auto weapon. It was fed from a 20 round magazine. During WWII the Army's tactical squad of nine soldiers was organized around the BAR. The Marines took this one step further. Their squads contained 13 men, and these were broken up into 3 fire teams, each with a BAR. The BAR was a very reliable weapon. The only drawbacks I have ever heard were that it was difficult to change the barrel. And it weighed 40 lbs.
The only flaw in the answer given is that the BAR did NOT wiegh 40 pounds. Correct weight is 20 pounds. And that is 20 pounds with a full magazine of 20 rounds Cal.30 ammo. I know. Carried one long enough.Although a reliable weapon, it did like to jam.
The BAR was also a favorite weapon of Bonnie & Clyde,and they met their end by it as well.