I recently had Kevin Rayhill build me a 7WSM on a Savage action. The gun shoots great but I have a question. I have shot Nosler Hunting Ballistic tips and Berger 140 VLDs out of the gun and they shot sub .5 MOA. The last group of Bergers shot one hole and was less than .3. My question is this. When I went to the 168 Bergers they did not group well. I used the same load as the other two. I used 68 grains of 4138SC and loaded them just off the lands (.005 off the lands). It shot well over 1 inch. Why would these be more difficult that the other loads. Thank you for your suggestions.