Bob 79,  If I have not already done so, Welcome to the Forum.  The mags for the 380 and the R-9 are not the same mags with a spacer.  The top of the can is cut different and  the springs are different . The spacer allows the mag to fit in the frame without a major frame change.  Alot of time was put into getting the mags right.  So far they work great.  Dan