It is 88.5 grains in real Weatherby brand head stamped brass. It has to be a 26" or longer barrel or you won't get the speed. It is possible to get this speed in Remington brass but back off and work up. It will be a stout load in the smaller capacity brass.
CCI 250 primers
This load closely mimics Roy's original load for the 300Wby. Only use in Weatherby barrels with spec free bore for factory ammo. Like factory ammo it will leave the very slightest of extractor marks that can only be seen with keen eyes in good lighting but they will be present. Brass should still last at least 10 firings. I loaded many at this level more than 20 times. This load has proven to be a sub MOA load in many different Mark 5 rifles. My best ever 100 yard group with any 300Wby was shot with this load out of a very thin barreled German made Weatherby.
Due to the primer shortage If you can't find genuine CCI-250 magnum primers you can substitute Federal 215 with no other adjustments.
As with any load data back off and work up in your own rifle.
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Last edited by Hired Gun; 11-15-2007 at 08:36 PM.
Reason: I forgot the exact load. Joecool set me straight. Thanks