I need to know what donor to buy for a 7 lrm. The 7 lrm parent case is a 375 ruger. What cartridges have the same bolt face that I could build off of. Could I just buy a long action and change the whole bolt? I have a few 30-06 action that I could purchase to build from would that work? What if I built a 28 nosler? What donor same bolt face and firing pin questions.