I can tell you it's "thin" in the SE corner. I looked for a used .223 all summer. I found a 7-08 at a little gunshop west of here someplace. In retrospect, probably should have bought that one. 2 .243s at Hardy's in Burlington.. Both had no-name scopes on them and he was higher than retail (3 - 3 and a quarter) on both of them. Cedar Rapids gun show had a .30-06, something big (.45-70?) and a handful of .17s.
I know - no help.. I bought a new one. Couldn't be happier with it. good luck.