The M1 in the American Rifleman
It may be worth calling attention to the scanned copies of the American Rifleman available online from back when it was a magazine you'd actually want to read.
American Rifleman 1923-2015 : Free Texts : Free Download, Borrow and Streaming : Internet Archive
The August 1938 edition is here with the article by Major Guy H. Drewry introducing the M1 to the NRA membership. So too is the April 1940 edition with the editorial, 'The Courage To Be Frank' expressing doubts about the M1, and the May 1940 edition with NRA staffer F.C. Ness's evaluation, in the Dope Bag column, of an early (muzzle cap) rifle, and exactly one clip, that he had borrowed. He praised some features; some of his criticisms, such as of the early sight which would not hold its zero, were justified, other appeared to be peculiar to the example they tested.