The only "trouble" with the waxed wads, is the weight of them. If shooting without a choke, (which tends to separate the wads from the shot column) the heavier wads will tend to blast
through or into the shot cloud after it leaves the muzzle, and 'blow' the pattern into donuts. I have seen these results when using normal-type wad columns in muzzleloading guns without
any choke. Of course, it also happens in non-choked modern guns made around the turn of the 20th century (late 1800's).
I have one such gun, a London gun which shoots fine with simpler wad column without heavy "lubed" wads.