Tracking Wartime Library #3, War in the Army #2 and World War Library 15...

Page Publications' Wartime Library #3 has a cover illustrated by Keith Chatto and was published c.June 1972:

The cover-featured story titled Ambush Patrol is the fourth story in this issue, and was originally published in Battlefield #3. The opening story in Wartime Library #3 is Amphibious Assault, which originally appeared in Marines in Action #6. It is possible that an earlier edition of this Page Publications issue was published featuring Amphibious Assault on the cover.

This issue was subsequently published as War in the Army #2 under another Chatto cover:

And some time later the issue was recycled as World War Library #15:

The cover is drawn from the splash page to the story Man Overboard:

 

Man Overboard is originally from Atlas' Navy Combat #16. 

I am certain there are more iterations of this issue to be unearthered.