Had bad results at the range with my newly rebarreled 6.5 WSM.
3 shots averaged a 4" pattern with 2.5" being the best "group". I am using a Savage 10 action, PacNor 8" twist polygonal rifled barrel, Burris Euro-Diamond scope. I got these groups while "breaking in" the barrel. The bullet fires fine (.5" and .65") in 2 other 260's that I have, so I don't think that is the problem.
I am thinking the problem could be the use of the factory plastic/flimsy stock. Another pattern I noticed was the nickel plated brass shot worse than the brass brass. I headspaced on a case that I was going to be firing.

I'll take any and all advice on possible solutions.

I would like to keep this rifle light. I have a heavy barreled 264 WM and want this to be a lightweight 6.5. IMO rifle stocks should be wood. If a synthetic material is used for a stock it should be used to reduce weight only. I don't like the feel or looks of syn stocks and only tolerate them as a weight saving means. I will take recomendations on quality lightweight replacement stocks, but if they weigh close to wood, I'll get a bright laminate stock from Stocky's.