never owned a char bull, but help work a couple of herds that do... they rarely pull a calf and raise some mighty fine calves off their commerical cows and the char bulls.
another even larger herd that i do not help work, only palpate for him, does not have calving problems either with his char bulls.
like someone said, a yellow char cross calf brings big $$ at the sale barns.
most of the bw problems with char has been bred out of em.. but like any other breed, they will have some. check your epds before buying a bull.
jt