Good Day,

Does anyone have any experience or data loading the 257 Weatherby Magnum with any of the following powders:

Vihtavuori N170, N570
Retumbo

Thanks for the help!

Not I
I use IMR 7828

quote:

Originally posted by df06:
Not I
I use IMR 7828

Thanks but unfortunately the agents aren't bringing IMR7828 into the country

I have not tried Retumbo, but I have used H1000 and RL25 with Barnes 100gr TTSX. I used Quickload to start my load workups and Retumbo seemed a bit too slow requiring almost 110% case fill for the 100gr TTSX. I am not sure all the powder would fit in the case. I don't like to use compressed loads unless absolutely necessary.

I use H870 with good success. I don't know how it compares to the powders available to you.

In regard to my previous post about Retumbo in the 257 Wby, I got curious after I made that post. And I got out my Retumbo and 257 Wby cases and checked it out and found that a max load of Retumbo with a 100gr Barnes TTSX fits just fine, right up to the base of the neck. So I was wrong about Retumbo being to slow for the case.
I even made up some test loads for the next time I head out the the range.

Yes, I imagine Retumbo would work fine. I hope so....I have 4 lbs of it :-)

Tried Retumbo in my 257. I used the 117 gr Sierra game king. Worked up to a max of 75grs with a Weatherby case, a Fed 215 primer with an oal of 3.265. Vel was 3377 ft/sec from my 24" barrel and accuracy was 1/2 moa at 100 yrds. Real great load.

All three of those powders are listed for heavier bullets in the 257 Weatherby. You are in luck.