Savage has made some small changes to the MKII 22LR rimfire line of bolt action rifles in the last several years. The major change is the newer "E" receiver. The "E" receiver is slightly longer then the early models and the magazine well has been moved forward on the 22LR rifles. The easy way to tell what receiver you have is the receiver's length. The "E" receiver is 7 3/4" long and the non-"E" receiver is 7 1/4" long. The 93R 17HMR/22WMR chambered rifles magazine well openings are still in the same location and have not changed. The only other difference is in the stocks inletting. The plastic stocks are inletted with a bottom metal cover for the magazine well that is about 4 1/4" long while the wood stocks are about 3 3/4" long regardless of caliber.