I am reading about it in cartridges of the world-it is in the obselete secton. It says that the lack of good factory loadings led to the demise. The only factory load for it was a 120 grain bullet at 3200 fps. Some people like using a little heavier bullet in the 6.5mm's. I.E. 140 grain. Also the 264 winchester, which also has faded in popularity had it beat on the velocity end. Lastly the 6.5 remington magnum was offered in the remington 660 carbine which a choice of either an 18.5 or 20 inch barrel. To achieve its advertised ballistics it had to have a longer barrel. I think remington is even still offering the 6.5mm magnum in its guide gun.