beretz,
I've had two .264's, and in the first one (a pre-'64 Model 70 Westerner, the model with the 26" barrel) Ramshot Magnum was the clear winner with 140's, getting a little over 3200.
The second one was a Ruger Hawkeye with a 24" barrel. Magnum was the winner with 130's, but RL-25 did best with 140's--though top velocities were only around 3100.
