Te biggest difference you will find between the marlin 22 mag and 17 HMR is the accuracy, the 17 HMR will almost always shoot under 1 MOA at 100 yards while ive found the 22 mags shoot about 2- 3 moa at the same distance. and also the 17 HMR has a flatter trajectory compared to the 22 mag. so i belive the 17 HMRhas a large advantage over the 22 magnum as long as deep penetration is not an issue. just my opinion.