The 264WM is based on the same brass as the 458WM, 338WM, the 7mm Rem Mag is also of the same dimension.
I started reloading for magnum centerfire in 1976. I bought a MDL 700, 7mag, dirt cheap. Few people on the MS Coast were interested in magnum rifles and it was rusting on a Gibson's display case for $100. This was also my start at reloading for magnum center fire.
I now own and reload for 340WBY, 300WBY, 6.5x284. I can get over 3000fps with 140 gr Berger, with RL 15, with no signs of high pressure.
Point is , I remember a statement from the Speer manual of 1975. It noted in it data on 264WM that it was the flattest shooting, and had the longest maximum point blank range of any comparable big game rifle of it's time. Speer also stated that it was the definitive barrel burner. That after as little as 500 rounds the muzzle velocity would deteriorate to 270 velocities.
You can still get considerable more muzzle velocity from the 264 WM than from the 270. Not for long though.
If you are going to hunt only this is about as good ballistically as it gets. It could last a hunter for a lifetime, but will never be a range toy.