Thanks for the reply. There is a dovetail ramp milled on the top of the chamber, similar to a .22 grove. It is stamped "FLAIG-ACE.MILLVALE PA" next line is"MADE IN AUSTRIA" The lower bbl(.222) is stamped "RHEINMETALL 55".
The lower monoblock is stamped "Cal. 20/76 Mag.", next line"Cal. 222 Rem.". Other than the S/N and proof marks, I don't find any other marks. It was obviously an import, my father acquired it about 40 years ago, used, I think. There is also a brass cocking indicator behind the lever on the top tang. The bbls are 23 9/16" long, the front sight is a beaded post on a ramp with a v notch rear sight located about 4" forward of the breech.