Just back from the range with some chrono.data on my 9.3x66.
Please be aware my rifle is custom made with a custom chamber and appears to produce higher velocity at any given charge than the factory rifles.I was working from the VihtaVuori Reloading manual,my rifle seemed to reach max velocity list at lower charges-another good reason to use a chrono. when reloading.I only tried to get within 50 to 100fps of the manuals velocity then stopped.
Reloading manual 4th edition
Sako cases,Federal 210 primers.

286gn Nosler,65.5gns N550,avg velocity 2513fps

320gn Woodleigh Solid,62gns N550,avg velocity 2330fps

These numbers are based on a small nos. of rounds and were measured 15ft from the muzzle.
Please consider this information worth what you paid for it!!!!!

+100% on using a chrono for load development(among other things)! I've got a factory production Mod70 in .25-06 that reaches max book velocities at 1.5grs under the max book recommended load. Not alot but enough to maybe cause a problem under the wrong conditions!

til later

Wombat…How is your custom chamber different from the CIP standard?