With the latest legacy stock sides you have an insert to fill the gap from long to short. In the older style stock sides turtlesniper was correct but now that is not the case. In the old style we had to machine out the stock sides to make a short action into a magnum as well as having to machine the "fixed cheek piece" part of the stock to make it suitable for adjustable cheek piece. Now the stock sides do not have to be machined and instead some trimming has to be done in some circumstances. They are also suitable for right and left hand, AICS, AE and AW.
Tom Irwin
Accuracy International