Robert Sherwood had some extensive write ups on the 6.5x55 and bullet performance for 6.5s, having recalled a handloader digest LONG ago in my former college library, I seem to recall the early 70s perhaps, in it I BELIEVE was info on the 6.5 Rem Mag, so perhaps since it's intro, perhaps 66-75 era.
I seem to recall he tested a 17.7" '96 Swede, a Husky w/23.6" or so, and a M600 in 6.5 Rem Mag. He discussed twist rate if I recall correctly and how his bullet test showed more upset w/faster 96 carbine albeit slower speeds.
Sherwood, Aaggard, Wooters, and a few others authors/articles on the Swede got me to finally try it in the early 90s and I am happy to have done so.
