Mini 14s... .223 or 5.56?

[SKS Ray]

I've heard Ruger Mini 14s can fire both .223 and 5.56 because of a chamber thats designed to work with both ammo types but does anyone know if this is 100% true?

I've got a ton of surplus ammo that I know shoots hot in my Mini 14 but I don't want to screw up the gas system or the rifle in general.

 

[OnTheRoad]

According to page 11 (page 10 on the linked PDF) of my Mini-14 owner's manual (http://www.ruger-firearms.com/Firearms/PDF/InstructionManuals/23.pdf), "The Ruger Mini-14 rifles are chambered for the .223 Remington (5.56mm) cartridge. The Mini-14 Rifle is designed to use either standardized U.S. military, or factory loaded sporting .223 (5.56mm) cartridges manufactured in accordance with U.S. industry practice."

I have used both in my Mini and have had no problems.