Ruger semi-auto ranch rifles

[Waddison]

Ruger's previous version of the .44 Magnum ranch rifle was discontinued and replaced with the current "Deerfield" model. Apparently, the "Deerfield" is gas operated like the "Mini Thirty".
Was the older version "blow-back" operated?
Waddison

 

[1KPerDay]

Both are/were gas-operated, but the new .44 deerfield has an "improved" gas system based on the Mini-14/Ranch Rifle.

http://www.galleryofguns.com/shootingTimes/Articles/DisplayArticles.asp?ID=107

http://www.huntingmag.com/rugers_guntalk/guntalk/

http://www.outdoorlife.com/outdoor/gear/fieldtested/article/0,20280,rifles-0040,00.html

http://www.recguns.com/Sources/IIID2b183.html