I have a P94 40S&W. I have a chance to get a complete set up in 9mm. That's barrel, slide, spring and rod with a 10 round mag. Would this work on my frame?

Jules: Don't think so. Until a few years ago, both 9mm and .40 S&W pistols had barrels that used a swinging link. When the P-97 came along. Ruger used it's locking system in .40 S&W P-94s, but not the 9mms. It also appears that there were differences in the frames before the modification of the .40s. Contact Ruger to be sure!