WB
I have a 6mm Ackley that is pretty close
Thursday, May 03, 2018, 19:34

to .240 Wby. The 6mm ackley is basically a blown out 7X57 and the Wby is a .30-06 necked to 6mm and a belt on the case. I really like H4895, good predictable, progressive propellant. Plenty slow enough for that case to give good performance. Just start low and work your way up.

Most Weatherbys have lots of freebore ahead of the chamber before the rifling is engaged. This allows for a serious charge that other rifles could not handle. The bullet can move forward a good bit and effectually gain capacity and lower pressure otherwise. The box of ammo says not to shoot in guns other than Weatherby and that is why. You will be able to work up a good hot load if it's factory Weatherby, if not just proceed like any other working the load up.