[Lurker]

“was shown using a Savage 99 chambered in .300 Savage,“

Sadly I let one of those fine rifles slip through my hands. Still have a couple boxes of cartridges for it laying around somewhere.

L

[marktwain]

I shot my first buck, in 1964, with a Savage 99 in .300 Savage.

The .308 Winchester/7.62x51 is a modified .300 Savage.

The Army thought the .300 would make a cartridge with near the power of the .30-06, in a more compact package.

In testing, they found the neck of the .300 Savage was too short for military use in semi-autos/full autos, so the increased the case length a bit and increased the neck length. Voila! the .308/7.62x51.

My understanding is the .223/5.56x45 is the result of similar experimentation with the .222 Remington magnum.