I just got this rifle on trade. Lyon & Lyon .500 3" BPE. I traded my A Hartman .577 with which I was not pleased. This rifle hits all the buttons in my book; high grade hammerless, big bore, light weight (8.5lbs), 28" steel barrels, light recoil, and very accurate(sub 2").

The best I can reckon is it was made by W&C Scott sometime from 1895-1905.