After shooting for nearly 44 years, I am still learning. I have been shooting and hunting with my Ruger M77 MKII with the boat paddle stock for almost 17 years, Until I found this forum, I was content with 180gr and 200gr "standard" bullets, the 200s were mostly Partitions and Speer Hot Cores, the 180s were a wide variety of cup and core. What I have recently learned is to not mix bullet types, I shot my rifle, with a clean bore, fired 2 fouling shots with 208gr AMax bullets, then shot for a group with 200gr Nosler Accubonds, they shot fine and right where they should, I then shot for a group with the 190gr VLD Hunting bullets, these shot just fine last weekend, after alowing 15 minutes for the barrel to cool, I shot the Bergers, they wouldn't group, and their POI was 3" to the right of where it was last weekend. I am only guessing, but it seems the Bergers don't care for the copper fouling of the Accubonds?? I only recently switched cleaners from Hoppes #9 to WipeOut and Boretech, I am thinking I don't need to use them every time I clean, unless I am switching bullet types. Ignorance was bliss.