It probably doesn't need to be said, but great care must be used when loading the fast "pistol" powders like Unique or 2400.  A double charge if gone unnoticed would be a disaster.
Harris also liked 11 grains of Red Dot.  I've tried that but again get elevation stringing that I don't when using 2400.

Great work with the Lee bullet and 2400 loads.  That looks klike their SKS bullet which I have and use in other rifles, too.  My patches come out black when shooting 2400 like that too.  I never have any leading and I've used stright out wheel weights for my plinking and practice loads and Lyman #2 alloy for my match bullets.  Liquid alox lube on 1400+ (155 grain bullets probably somewhat faster) may be OK..seems a bit fast for liquid alox to me.  That's a very cool looking rifle and good shooting.