I've been wearing progressive lenses for more than 15 years, and they really haven't affected my shooting. Now, I don't have a real strong prescription, and my lenses are not terribly large as to change my anchor, but they work just fine for me.
In fact, they may even help my shooting. When I don't turn my head enough toward the target and instead look across the lense rather than straight through it, there is some distortion. That's a signal for me to turn my head more toward the target. In effect, the progressives help make sure I don't align my eyes improperly on the target.