100-1000 USD
No such weapon in the Ruger line
100-1000 USD
The Ruger Mini-14 Ranch Rifle marked as .223 can safely fire the .223 AND the 5.56 NATO military cartridge. The Ruger Mini-14 TARGET model should only fire .223 ammo- no 5.56 mm
100-500 or so
100-435 USD
It depends on the condition of the rifle.
Best left to a trained factory representative.
100-460 USD or so
No, this is a dedicated .223 Remington chamber, and that's the only ammunition which should be used with this rifle. While the two rounds are matching in dimensions, they are not identical.
450-600
Depends. If you mean the Ruger Mini-14 or Ranch Rifle, yes, you can. It is chambered for .223 and 5.56x45 ammo. If you read the owner's manual (available on the Ruger website) it will tell you that on page 13. The Target Model is ONLY for .223. Of course, the 6.8mm and the Mini-30 use different ammo entirely.
250 or so