Here is the article which mentions the brittle Eddystone receiver:
http://www.fulton-armory.com/LNSpringfieldLowRes.pdf
It is primarily about the early Springfields but there is one Eddystone that they did their "test" on, although reading it again, this may be a receiver that was sent to him and cracked when being rebarreled.
On the receiver cracks, nearly all the articles on this were from message boards similar to this one and seemed to be "words of wisdom" passed down from person to person so accuracy is questionable.