Isn't it true that these two rounds use just about identical grain weight bullets pushed at almost identical muzzle velocities. If that is so then wouldn't the .357 sig be just about the best possible choice for a self defense round, assuming your choice is a semi auto instead of a revolver. If I'm not mistaken I think these two rounds can be loaded to about 1,400 fps.
What are the downsides to using .357 sig?

