MkI Bipod - plum colored mounting ring

[browningautorifle]

When the metal has a high nickel content and the blueing salts aren't strong enough it will turn purple.

Or a high degree of nickel in the steel and the item was not pickled correctly in acid before the bluing process

I said that one too Wheaty, they didn't believe that one either... Lots of Winchesters went purple because of odd mixtures of Depression era steels...was our suspicion. Winchester had boys with pails gathering every metal object for his mill. The military stuff might have high nickel because the steel batches weren't so far from the stuff used for the armor plate. Need a real strong solution then. The OP's piece is highly polished and that ain't factory.