Looking to build a 308 Savage, so I am looking at a rimfire to use to keep the practice price down, and I just want another rimfire. Been looking at the 22LR, and the 17HM2 or maybe the HMR. Looking for something that will be similar to the 308 in ballistics, so that I can get doping practice. Wanting to go with the Savage so I can get the bolt and trigger down, and will scope it similarly. Which of the three cartrideges would be better for cheaper practice for CF gun and doping?