Nobody knows the exact percentage of lefties. It isn’t large but, being both left-eye-dominant and left-handed, I believe that the incidence of left-eye dominance exceeds the number of actual southpaws. There are degrees of eye dominance, but there is sound argument for shooting on the dominant side, simply because most sighting systems rely heavily on use of one eye. Like most lefties, I grew up with right-handed firearms. However, for those who have left-handed family members, there is strong argument for left-handers using left-handed firearms.
One word: Safety. Most repeating firearms eject to the right, for the right-handed majority. In the event of a catastrophic...