Is it me or is this the second time in about a month we have gone down this road with someone?
The Mini-14 IS gas operated. it has a gas system I can't think of too many, outside of the H&K, .223 rifles that aren't gas operated.
The HK is a "delayed roller locked blowback" . In it's lightest rendition it is, IMO a bit heavy for the round.
Other than the HK the world of semi auto .223 and larger operates on gas.