The larger the case capacity in relation to the bore size,the longer the barrel that is generally required to burn the powder.If you use a 24" barrel on a 300wby you aren't going to gain much over a 300win mag other than much more expensive factory loads ,more recoil and more muzzle blast.All ballistics provided by weatherby for the 300wby are for a 26" barrel.With a 24" barrel your velocities will be approximately 100fps less which hardly makes the 300wby worthwhile.