Karcraft I think posted some manufacturing information a while back.
If I recall, up until about 1969 they were forged steel, the flycuts on the outside are caused by milling of the tapered lugs.
After this time they started using sintered powder metallurgy, and these were good at the time.
My thoughts...
With the demise of Rover production there is great variability in Quality of what we get now. I don't know if it's material, production method, poor machining or what.
Note that the 3 lugs are designed to be hard and the rest left much softer, perhaps this makes keeping them round a challenge.
ps. I was a production engineer in a previous life.
