I'm curious, prompted by a video on the P-47 which has EIGHT 50s with 350 rounds EACH gun..

You should be able to google this and find an exact number.

A quick search turned this up: .50 Caliber Browning (12.7 x 99 mm) Ammunition

There are many different .50 rounds, these are a few, with specification weights. I have full and complete specs on all .50 rounds in the US inventory. You could say 1700 grains as a rough weight.

M2 Ball 1813 -73 grains
M8 AP 1764 -78 grains
M17 Tracer 1737 -68 grains
M20 API 1738 -76 grains

So roughly, four cartridges to the pound.

Yes, not counting the links which don't weigh that much.

100 rounds of cal .50 linked 4 ball M33 1 tracer M17 using M2 or M9 links weighs 35 pounds.

Cartridge, Caliber .50, Incendiary, M1 or M23 (blue tip) was popular for aircraft use. On impact it made a brilliant white flash and was useful in setting fuel and flammable structures ablaze.

Cartridge Caliber .50 tracer M21 aka "headlight"tracer was designed to be highly visible from the front. It only burned for 600 meters as opposed to 1600 to 1800 meters for conventional tracers but is was intended to unnerve enemy pilots by making sure they knew they were being shot at.

What does your table mean by '73 grains'? And before that you wrote "...1700 grains as a rough weight'.

TYVM; I did NOT find that one.

That's the range they fall into. 1813-73 = (1813-1873)

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That's just somebody talkin.

What it means is that the military spec calls for 1813 grains minus 73 grains for the M2 Ball, i.e., the tolerance is 1813 grains maximum weight and (1813-73) 1740 grains minimum weight. Anything between 1740 grains and 1813 grains meets the weight spec.

A single M9 link for the .50 caliber has a spec weight of 253 grains. So the combined weight of a round and a link would be around 2000 grains.

I thank all of you for your contributions.. Six-odd-hundred pounds are a LOT of ammo!

It are a lot till one considers that is 10 three second bursts.

The early AN/M2 aircraft gun has a cyclic rate of 750–850 rpm. (about 25 seconds of firing time)

In 1939, Chief of the Air Corps, MG Hap Arnold sought a cyclic rate greater that 1000 rounds/minute. After a period of development, on 6 December 1944, a Research and Development contract was placed with Frigidaire for 100 T25E3 guns. The first gun was delivered 6 January 1945 and the hundredth gun was delivered 12 February 1945. The T25E3 gun was standardized as the M3, and 2,400 had been made by September 1945.

By the end of WW2 the standardized basic machine gun fired at the rate of 1,200 rounds per minute. It was also the armament used on the F-86 in Korea.