In the early 1980's Murray Comics dipped a tentative toe into the digest-sized comic market. Various genres were represented, such as
romance comics,
westerns and
horror comics.
I have copies of the following war digests:
Fightin' Army NN
Fightin' Marines NN
Nightmare Mission NN
Like the non-war samples above, these issues are distinguished by the fact that the rear cover is a reproduction of the front cover, which was not typical of Murray. Of course, Murray had previously published digest-sized series, notably a long run of romance comics and, in the mid-1960's, Superman Super Library, but these cross-genre samples from the early 1980's form a particular subset of Murray digests. The timing and price point broadly coincides with the Yaffa digest-sized comics, which may have triggered this program.
I don't have enough information or samples at the moment to assert or conclude too much, but it appears to me this subset was published over a relatively short time span - maybe a 12-18-month period between late 1981 and end of 1982.
The romance editions incorporated the Murray Romance Library logo. I think of this subset collectively as the Murray Library series, so the westerns form the Murray Western Library, the war issues become the Murray War Library, etc. I don't recall seeing a science fiction issue, but I wouldn't be surprised to see some pop up.
I say they broadly coincide with the Yaffa digests in timing and price point because, if my timing is accurate, the Murray issues appeared with a $0.60 cover price just as the Yaffas changed to $0.70, and persevered as the Yaffas inflate to $0.75, so the dating is subject to review.
Anyway, this is just my musing on these issues until more information and samples come to hand.
Update: The cover of Nightmare Mission was originally published as the cover to Charlton's
Fightin' Army #124, May 1976.