I have one 6.5 WSM and another on the way. Both have different chamber configurations. My first 6.5 WSM is in a Rock Creek #3 fluted 26 inch barrel on a Model 70 that was originally a 300 WSM. The Barrel is very light and the stock is a all graphite MPI. With Talley light weight mounts and a Simmons Altec 4.5-16 Scope it weights 7.5 lbs. Recoil is substantial.
I also have a 6.5 X 284 with a heavier 26 inch Bartlein barrel on a Lone Wolf thumbhole stock that weighs 2 more pounds.
I have focused on the 120 Ballistic Tip and 130 Accubond bullets for mule deer hunting. All bullets are hexagonal Boron Nitride coated HBN. I have a friend who built a similar rifle to mine and has shot the Accubond bullets at a pronghorn and a mule deer at over 300 yds and they have penetrated completely with relatively small exit holes.
I use a Wilson seating die that was cut with my reamer. I consider it the key to concentric ammunition. The cases are sized with a .296 bushing in a Redding Type "S" full length bushing die.
I have tried the 85 and 100 gr Sierra varmint bullets with reduced loads to increase trigger time and reduce the barrel wear. I seat these with a separate Lee sliding sleeve die.
I might add I have extensive experience with the .264 Winchester Magnum in both factory and custom barrels.
I have tried Reloader 22 and Reloader 25 extensively and neither velocity or accuracy are as good as Retumbo. When I ordered my barrel and reamer, I expected to use R-22 and R-25 with Fed 215 primers. I have tried the new Hodgdon Superperformance (about R-19 burn rate), Alliant 4000MR (about 4831 burn rate). I have used IMR 7828, VV N-560, Magpro and Winchester 780. Velocity with these "new" powders is not impressive in this application. Magpro is fabulous with 140 gr bullets in the .270 WSM parent cartridge. I is at least 100 fps faster than any other in this .270 WSM application.
I use Norma brass and anneal it frequently.
I currently use Retumbo with 130 gr Accubonds. Ramshot Magnum can be made to go just as fast as Retumbo but I have not achieved comparable accuracy. It is difficult to exceed 3300 fps with this combination. With HBN, the first shot out of a clean barrel is often right on the center of the target and the group. This was not the case with fowling rounds without HBN. I can get the occasional 3 shot group under an inch. I have shot under an inch at 200 yards as well. Surprise he barrel heats up quickly.
Is anybody exceeding this velocity with these bullets>