By 1924, the 9,3X72R was standardized and I am not sure why the dimensions are what they are. Hopefully Ford will be by in a minute.

[Linked Image from thumbs2.imgbox.com]

Emil Eckoldt was the only maker that used a Heart as a Trademark. Look for his trademark or initials elsewhere like on the Standing Breech.....


Hochachtungsvoll,

Raimey
rse