[Yo-Yo]

Please see my post # 9. Early series mini 14’s should not fire 5.56.

I'm not sure where you got that information, but you were misinformed.

Early Mini-14s were marked .223, but had 5.56mm NATO chambers and are safe to use with any 5.56 NATO factory round. It states this clearly in the instruction manual.

See the original manual for the first gen Mini-14 here:

https://ruger-docs.s3.amazonaws.com/_manuals/mini14-180.pdf

Ammunition:

The MINI-14 is designed to use either U.S. Minitary, Commercial Sporting, or other .223 (5.56mm) caliber ammunition manufactured to U.S. indurtry standards.

[Yo-Yo]

Please excuse the typos. I couldn't cut and paste from the .pdf manual, so I hastily typed it using notepad and neglected to use spell check before posting.

Ammunition:

The MINI-14 is designed to use either U.S. Military, Commercial Sporting, or other .223 (5.56mm) caliber ammunition manufactured to U.S. industry standards.