Initially the 40 Newton was listed as the 40 Adolph Express in the earliest Newton catalogues as Mauser rifles that could be converted to the 40 Newton. During the early years the minimum caliber for dangerous game in the British territories were at least .40 caliber. The cartridge was listed first in the Supplement to Catalogue B of the Buffalo Newton Rifle Co and it was stated that the detail about the cartridge would be finalised by September 1925. In a letter by Charles Newton the case was to be the 35 Newton necked up and loaded with a 350 grain bullet at 2,800 fps and a muzzle energy of 6,125 ft/lbs. Lawrence S. Wales in his book titled The Newton Rifle Handbook – A Collector’s Guide to the Newton Rifle and Related Items mentioned a gunsmith, dealer and collector O.H Elliot owning a 40 Newton rifle, apparently one of only four such rifles made, and they were First Model 1916 Newton Rifles.
