There is a VERY big difference in performance with the 17 hmr, especially at 75 or more yards. 2350 fps vs 1200 just to start. The 17 and 20 grain TNT penetrate well and kill on larger game, the vmax style 17s are very explosive on gophers.I can change out my 22 lr barrel on my CZ 455 to 17 HMR but didn’t think I would be gaining much. Honestly I never looked at the numbers. Maybe I’ll take a look at what I would gaining.