I also thought that the factory CC on my Miroku 1892 was sufficient until my 1873 returned from Turnbull; now, my 1892 looks (to me) like a cheap, iridescent coating. In turn, my 1892 is at the Winchester Arnold, MO warrantee facility for the 2nd time in seven months for cosmetic problems to include the second time returned because the factory CC rubs off the frame very easily - bare steel quickly appears with a gun oil wipe down - the CC just wipes off - I am interested to see what action Winchester takes with this rifle and it’s second return for the same problem - the factory CC just does not stick to the frame.
Anyway, now it is obvious to me that there is no comparison between Miroku and Turnbull CC - with both these CC processes and as with most costs in life, I got what I paid for from both Miroku and Turnbull.