This was a Westley Richards 1897 falling block rifle in .450 caliber. It had at one time been rebarreled and whoever made the sling eye didn't get the shape of the sling eye quite right. It looked more like that of a Rigby rifle and had a deep machine mark in the base as well. I reshaped the existing part to more accurately reflect the shape that would have been found on a Westley Richards.
The sling eye as received
After a bit of file work