Pete, this is barrels made from Whitworth's steel in 1908. There is no Whitworth's trade mark, but two numbers only 35857 and 35858. I saw allmost the same barrels made from the same steel, but earlier made and barrels beared one number only.


Whitworth pattented fluid-compressed steel process aprx in 1855, so Henri gun could bear Whitworth's number 5435 in 1877. Just my wild guess.


Geno.