Checkman, thanks for posting! Keep it up!

"Desperate attempt" is right on. I think personally the really interesting story here is the "non-story", meaning, the essentially complete failure of the NE guns to provide any significant advantage or useful service under the conditions of trench warfare. The story is the desperation that all nations experienced when confronted with static warfare conditions and the development of weapons to gain advantage. Recoil, muzzle blast, "smoke" are all cited in various sources as factors insuring the failure of the NE rounds in military service, and I might add my surmise that poor ballistic effect and practical accuracy is also another.

Hitting a typical loophole plate from a realistic, camoflaged position at, say, 300 meters would be nigh unto impossible with an Express-sighted .500 NE or some such and even if by luck of the draw a fellow dropped one on target, the best that would occur would be a clanging of the gong.

I have wondered, but never read, if any similar attempts were made by the Germans, i.e. the use of "elephant calibers" in the trenches. They did, of course, introduce the 13mm Mauser round in '18, but that is another bird of an entirely different feather. I have read of the use by German forces of various hunting rifles for sniping purposes, brought to the trenches by Försters but never read of an attempt to specifically use them for loophole busting which, of course, they would not have been much good for.

Truth is, loophole penetration never was the ultimate direction of sniping equipment. Targets of opportunity and open targets and more exposed targets {esp. machine guns, both the gun and gunners, etc} were. Artillery {HE, frag or later, gas} or machinegun fire were, of course, also used to remove sniping threats. My experience with the .303 against plate of a variety of types proves to me at least the generally poor properties of the cartridge against such targets. In fact, Labbett & Meade extensively treat the attempts by the Brits to develop a truly effective AP round for the .303, an attempt that never was very successful.

On a somewhat related note, by 1943, the USA essentially discontinued the use of pure lead core ammunition {150 gr M1906, 152 grain M2 Ball} and the lion's share of our involvement in WW2 was fought with a preponderance of 163-168 grain steel core AP.