Mike,thats a tall order.Graeme Wrights book ,Shooting the British Double Rifle,is a good reference.DGJ articles can also be useful,an article by Frank Findlow put me on the right track for an early H.Holland .450 express the I had struggled with for years.
My rifle has Henry rifling which is tapered from.467 at the chamber to.458 about 10" down the bore,it will only shoot a tapered bullet!I recut an old lyman mold on my lathe and ended up with a 285 grain bullet that measures .468 at the base and.451 at the nose over the paper patch.With this bullet and 46 to 47 grains of 4198 I can consistently shoot 4" (or less) groups at 100 yds.
I left out many details,such as dacron fillers,custom dies,etc....
