I own the Wby 257 Mag with 26" barrel. I shoot the 100gr bullet at a reloaded 3500 fps new bullets from Wby go 3600 or 3700 fps and the 25-06 I think can go 3200 or 3300 fps.

You will lose about 50 fps per 1"less of barrel. I don't know if this will help or not.I got 50fps increase with my 300 win when I had another longer barrel put on it. I went from 32" to 34" and that added 100 fps to my rifle.

I have a new one and so far it has shot great. I have only worked up one load using a 115gr CT BT and IMR 7828. 2 1/2gr under max using the nosler book and my chrony tells me is going 3280fps and no pressure signs. After 3 or 4 shots it really gets hot and the groups start to climb. Even with the 24in barrel you will easly surpass a 25-06. First day of deer season was Sat. and I missed a easy 180y shot using this load. This is the first time I have missed anything in years, but I had been perfect when i practiced with this gun and load out to 400y using shooting sticks at my range. Going back out this afternoon maybe we will see how this load and gun will work or maybe the operater is just getting old.
Hope this helps. TDV