Re: .257 Weatherby - Hodgdon RETUMBO
Several days ago I broke in the Krieger barrel (7 twist)in my custom 257 Weatherby using AR2225 (HRetumbo in US)with the Wildcat 156 grain ULD.
It gave excellent accuracy right from the start as I worked up from 60.0 to 65.0 grains of AR2225. The 65.0 grain load produced a .280 3 shot group, and a .485 5 shot group with the 4th shot pulled low spoiling a potential .300 group.
Unfortunately my CED chronograph didn't work, so I have no velocities to report. Thankfully the OZ agent sent me 2 new sensors (free), and the chrono is working again, so in about 1 hour I will head out to chrono loads of AR2225, AR2218 (H50BMG in US), and H870 with the 156 grain Wildcat.
My Norma 257 Weatherby cases hold about 78 grain of AR2225 to the bottom of the neck. So based on that, I believe there should be enough capacity to work up to maximum pressure with HRetumbo using the 110 grain Accubond in your rifle. Good luck on your testing. Brian.