I found pure lead in RB's just fine for moose. In a muzzleoading rifle shot with a cloth patch around the ball, pure lead is necessary for offer a good fit and tight seal.

I do not believe in having to wipe the bore between shots. THAT I find to be unethical, due to sometimes needing a fast second shot.

In the bore-side barrels, actually from about .54" upwards, a paper ctg. with round ball included seems to work just fine. Too, a slow twist, here I speak of a 80" or slower twist with shallow, .005" top .008" deep rifling will allow a WW ball to be patched effectively in cloth. The faster twists require a tight fit to ensure no gas escapement. My .69 cal English-styled rifle with 66" twist would not allow more than 82gr. of 3F or 95gr. of 2F to be shot with WW balls due to gas cutting of the patch, fouling and subsequent innacuracy. I couldn't use a heaveir patch due to the hardness of the balls - catch-22. For some reason, 2 wraps of .003" paper (.006" per side- total .012" and .685" ball) gave superb accuracy with WW balls in the rifle's .690 bore with 66" twist (.012" rifling). I assume the wadded up paper protected the ball and paper patch from being burnt through. Not once did the paper catch fire, onmly confette reigned, yet I shot these with 165gr. 2F. They delivered the same velocity as patched pure lead balls encased in .022" denim with the same 165gr. charge. Accuracy was 1-1/2" or better for 5 at 100 yards.
; More experimentation needs to be done in the .54 thourgh 62's with paper patching (as in military paper ctgs. the world over).
We use WW balls not for increased pepetraion, but for cost effectviness. Ww's are cheap comparred to pure lead.