continued
During parallel testing of the T44E4 (future M14) and the ArmaLite AR-15 in 1958, the T44E4 experienced 16 failures per 1,000 rounds fired compared to 6.1 for the ArmaLite AR-15.
[5] Because of several different .222 caliber cartridges that were being developed for the SCHV project, the .222 Special was renamed .223 Remington. In May 1959, a report was produced stating that five- to seven-man squads armed with ArmaLite AR-15 rifles have a higher hit probability than 11-man squads armed with the M-14 rifle. At an Independence Day picnic, Air Force General
Curtis Le May tested the ArmaLite AR-15 and was very impressed with it. He ordered a number of them to replace
M2 carbines that were in use by the Air Force. In November of that year, testing at
Aberdeen Proving Ground showed the ArmaLite AR-15 failure rate had declined to 2.5/1,000, resulting in the ArmaLite AR-15 being approved for more extensive trials.
[5]
https://en.wikipedia.org/wiki/.223_Remington#:~:text=It%20was%20developed%20in%201957,
@Blackvegetable