[.45cultist]

Originally Posted by HaplessOperator

No. It wasn't.

I know this is an ultra-old comment, but this is going up for anyone that comes along so they're not being fed BS; practically this entire forum thread is full of fuddlore and misinformation, along with a side of having a fatally flawed understanding of ballistics.

The .223 Remington round was developed from the ground up to meet CONARC (forerunner to FORSCOM) requirements for a new land service weapon in 1957, with the primary requirements being the ability to penetrate both a steel plate 1/8 an inch thick and a steel helmet at 500, while remaining supersonic to the same distance, and with the same MOA out of the test barrel as the M2 cartridge, with the project being managed by Remington, Sierra, and Fairchild.

This round was later adapted by FN to generate higher chamber pressures and standardized as the 5.56x45mm round used by NATO. It was never designed as a varmint round, but its extremely flat trajectory and high velocity make it an exceptional choice for it, in addition to its fantastic ballistic performance against two-legged varmints.

He's right. Remington made the .223 for the Army's specs at Stoner's request.