What grip is she using on the rise? Does she roll it off over the side of the index finger, or does she use the inside of her index finger to snap into and under (bent finger grip?)
What would the difference between a bullet spin-rise ball, and a screw ball?
To be able to compare the two we would need to have a proper definition of a "screw ball". The screw ball could mean many different types of pitches since a true screw ball spin (the opposite of a curve ball) does not exist.
I was under the impression that a screw ball would have bullet type spin, spinning like a screw.
I would agree, but that would also mean it doesn't move like a screw is supposed to move.
A screwball is supposed to spin and break in the opposite direction from a curve ball. It's very difficult to get enough of the proper spin to get a good amount of break. This is largely an anatomical limitation. The best you can get is a tipped bullet or top spin pitch with a minute amount of movement. Generally the attempt to throw the right spin results in bullet spin and most pitchers are clueless about it.
Most screwballs are simply stepping open to create a bigger angle.
In this area pitchers attempt to throw screwballs with a hand/finger action that is the opposite of a rollover curve. They try to bring the fingers to the inside of the ball but keep them pointed down, and throw a horizontal spin opposite of a curve. Some also step open but it's not very noticeable.
