Frigidaire Division of GM World War Two Products: 363,000 .50 Caliber Browning M2 Aircraft Machine Guns, 1,000,000 spare .50 Caliber Machine Gun Barrels…Frigidaire engineers made over 500 design and manufacturing changes to reduce the cost of the machine gun to 25% of the original cost, using mass manufacturing techniques.
EDIT:
Apparently in 2015, some active-duty unit sent in M2 Browning Serial #324 for maintenance. This was the first time it had ever been sent in for maintenance.
In more than 90 years of existence, the receiver with serial number 324 has never been overhauled.
“Looking at the receiver, for its age, it looks good as new and it gauges better than most of the other weapons,” said John Clark, a small arms repair leader.
https://en.wikipedia.org/wiki/M2_Browning
Apparently at one point – I assume during the war – Frigidaire, of all companies, was manufacturing M2 Brownings.
kagis
Apparently they made quite a few, actually:
https://usautoindustryworldwartwo.com/General Motors/frigidaire.htm
EDIT:
Apparently in 2015, some active-duty unit sent in M2 Browning Serial #324 for maintenance. This was the first time it had ever been sent in for maintenance.
https://www.army.mil/article/150794/Making_the_old_like_new