#6 (Feb-Mar 1964) "The Day Doc Turned Robot" (vs. the Gas Gang)
#7 (Apr-May 1964) "The Living Gun"
#8 (June-July 1964) "Playground of Terror"
#9 (Aug-Sept 1964) "The Robot Juggernaut"
#10 (Oct-Nov 1964) "Revolt of the Gas Gang"
#11 (Dec-Jan 1965) "The Floating Furies"
#12 (Feb Mar 1965) "Shake the Stars" (the Missile Men from #1 return)
#13 (Apr-May 1965) "Raid of the Skyscraper Robot"

Hopefully the titles give some idea of the flavor (and the covers can be seen at www.comics.org).

I still can't believe that they left out the "Metal Facts and Fancies" pages from the Archive, knowing what a big part of the Metal Men experience those pages were to the original readers.