You could always ream that chamber to a .300 Ackley Magnum, which is simply a .300 Weatherby Ackley Improved. It pushes the walls out and the shoulder forward to a 40-degree angled shoulder instead of that rounded Weatherby/Venturi shoulder. The Ackley shoulder design is supposed to be better on brass life, too. You can even use your .300 Wby brass, and your .300 Wby neck sizer die to size the necks. I've been doing that for mine till I can get the money to have some custom dies made ($250-350). Kind of a temporary solition to an expensive problem.
.300 Wby (left) formed .300 Ackley (right)
"I'm just a peckerwood who lives in the hills with too many guns..." - Bob Lee Swagger
"Give me a minute...I'm good. Give me an hour...I'm great. Give me 6 months...And I'm unbeatable." - Col. Hannibal Smith
Originally Posted by WildRose
The 284 is to the STW what a tricycle is to a Ninja.