R.G. Robinett
"That'll never work."
Winchester 6mm jackets, sold by Hodgdon, Inc. - how OLD would they be - just curious. They were pretty poor jackets: wall-thickness variation well in excess of 0.001" But, regrettably, I went ahead and turned them into bullets for a decent fellow.
He also had these, complete with a 1964 newspaper page stuffed inside. These had much more uniform wall-thickness (0.0005"), however, a contemporary 6mm/.243 core (Hood) would barley enter the mouth, then stop! Cores from my Rorschach .224 core-form die would barely fit into the bottom! I elected to pass on converting these, as they not only need and extra LONG .22 core, but also, were well tarnished (with a good boiling, and citric acid, correctable), & I don't need the extra work. Hell, I probably ruined the "collector" value of the Winchesters, which, by the way, were sparkling clean. RG