Gents gave the scotchbright and oil a go and it sure helped. I got a .71 bag mould from Track of the Wolf, and cut a long story short, worked up to 4 drams of Fg goex a heavy denim lubed patch and lo, no shooting to point of aim at 50 m off the bench, 5 inch group.
The bore is really starting to slick up nicely , recoil with the big charge was actually quite pleasant off the bench. I may go to a thicker patch when I can find the material. All the denim patches after being shot shewed no sign of tearing or burning through. I just need to shift the rear sight to the rhs a little and the rifle will be bang on. It is a bit like hurling anvils down range !! I reckon with a little more tinkering the group will still come in smaller. I do not expect target accuracy from this old girl but it should be good enough to hunt with. I prefer to use a slightly smaller ball in my long rifles and thicker patch as I can load without a short starter. I guess it will be a short starter for this rifle. I did wipe the bore after about 6 shots or so before continuing.