Hardpan,
If you are stuck on using IMR 4831 the Nosler #4 manual lists the following maximum charges for the following bullet weights:
100 grain bullet (partition/ballistic tip) - 68 grains
115 grain bullet (partition) - 64 grains
120 grain bullet (partition) -...
Bose,
First of all, welcome to the forum.
Second, I may be the one that started the thread you are referring to. Yes it is possible, and yes I am doing it. Lube the case up with Imperial Wax and one it throught the .257 Weatherby Die adjusted for a "crush" fit and that is all there is to it...
Got out Saturday night to shoot a few .22 shells with my two boys and in the process I got to shoot one group out of my .257 Weatherby with a load that I have wanted to proof for quite a while. I have attached a photo of the target with the applicable information. The only thing not listed on...
Here is a link you might find useful as well.
http://www.alliantpowder.com/products/n ... by_Mag.htm
Not quite sure why the same charge weight for the 87 grain and the 100 grain, but should give you some ideas to add to what you have already experienced.
I tend to disagree with the statement that RL25 is too slow of a powder with the 100 grain bullet in the .257 Roy. This cartridge begs for the slower powders.
If you have tried 71-75 grains of RL 25 with the 100 grain Hornady and turned out the groups like you mention I would say start at the...