17HMR and 17HM2 are not the same caliber. The 17HMR is a magnum caliber and the 17HM2 is a 22LR necked down. You should never use a 17HMR round in a 17HM2 firearm or vise versa. You should only fire the caliber that is stamped on your firearm's barrel.
What is the difference between the 17HMR and the 17HM2?
