I appreciate all of the good information that members have sent. Even though I have been hunting and caring for rifles for over 50 years, the Magnum arena is realively new for me. Thus far, I have ordered some Barnes Triple X to try, for as previously reported, the Bear Claw and Grand Slam, both in 180gr, did not produce acceptable groups on a consistant basis. I did use Birchwood Casey "Bore Scrubber" on the bore. That product promises to remove copper build up, but I could barely detect a slight amount of green on the first patch and after that, saw none. I allowed the rifle to sit several minutes between swabbing and each patch came out clean. Therefore, I am ruling out copper build up. No?
I also need to get some RL25 and IMR7828 to test, as the MagPro does'nt seem to do well, even with much reduced loads, but I will try MagPro with the Barnes Triple X. When I phoned the local propellent supplier, from whom I got the MagPro, he claimed that there have been problems of consistancy with both RL25 and IMR7828. I am skeptical enough to believe that he simply does not stock either propellent and is still pushing MagPro.
The men who sit around chatting at Seitzland Rifle Club in New Freedom Pa are getting tired of my flailing away with the 300RUM each Tues and Thurs, but I will not again go hunting with the rifle unless I am confident that I can kill that at which I aim! <8^)
Any other suggestions are appreciated.