Just an update: I found some 200 grain cast bullets from a company in Montana and load up some test loads. Found a load that shot 1" groups at 50 yards with open sights...powder was Winchester 748 and this was the most accurate load I've found, so far, of either cast or jacketed bullets. The load was even more accurate than the two factory loads I've tried.
So much for the microgroove myth!
So far I've tried WW748, IMR3031, H414, IMR4064, and H4895. Found a nice, accurate jacketed bullet load using the H4895 and the Hornady 200 grain RN.
Still have one or two more powders to try, but I think I'll be buying more 748!
