I believe the bullet you have chosen will be too long for the 6.5 Mag. I tried loading 129gr SSTs for my 2 rifles and the 2.8" magazine became the limiting factor when the ogive was half way into the neck just so I could load them in the mag. That was probably a major reason Remington only loaded stumpy 120gr Core-Lockts in factory ammo. My practice load is 120gr Bal Tips and hunt with 125gr Partitions. Both sit over loads of 59gr of RL-22 and a Fed210 primer.
Have fun with your 6.5 Mag but this round is not very forgiving due to case length vs. magazine length.

George


Dad always said, "Nadie Nacio Ensenado" (No One Was Born Taught)