Is there a difference in performance in normal Large rifle primers or Magnum Large rifle primers when loading for 7STW? Area conditions will be high altitude 8-11K feet, cold temperatures, moderate winds and either long flat ranges at the higher elevation and steep angles at the lower elevations. This will be the first time I have worked up a new load for my (new to me) 7STW. I - just like everyone else - am running into backorders for large rifle primers. I have found some large rifle magnum primers but do not know if I can feed them to my 7STW.