Read the posts on Benchrest.com by gunsmiths and shooters who have built the 6.5 WSM, most concur greatly overcapacity and barrel burner! Most have recommended that the case be shortened by about .200 to .225. That seems to be recommendation at this point. Would recommend that you wait until dust clears unless you have about $1500 for reamers, barrels and dies and replacement barrel if it does not work out. Winchester right now has some real quality problems with brass. I shoot 1000 BR with 300 WSM. Seems you only find one of 4 cases that will work. Case heads all over the scale on thickness and size. Weight will vary by as much as 7-8 grains in one lot of 100 cases. Primer pockets are funnelled into the flash hole instead of being flat so you cannot uniform. No one makes a powder funnel that will fit the case, take blue bonanza and dremel tool slits in side to slide over case necks. RCBS makes a # 43 shellholder and Redding modified their #6 shellholder about 1-2 months ago to fit, but no markings to differentiate new from old. Even then found cases that will not fit in either. However once you get some cases it will shoot. We just had VA 1000 BR state championship and 300 WSM took 1st and 3rd in Heavy gun.