I am looking to relaod for my cousin who has a very old Weatherby Mark V 257 wby mag. The issue I am running into is this particular model has a 1:12 twist barrel. He wants to shoot 100 gr or larger but so far the only bullet that a stability calculator will get over 1.5 is a 100 gr Speer Hot-Cor. Does anyone on here have any experience loading for this caliber with such a poor twist rate? If so, any recommendations would be appreciated.
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257 Weatherby Magnum advice
- Thread starter creedman12
- Start date
There are a lot of solids like 80 grain Barnes X and 90 grain GMX in 257 that would work in that twist barrel. Probably be 3500-3700 FPS with the right powder.
The good thing about the 257 Weatherby is that even with shit BC bullets it flies very flat.
Creedman12 i want to commend you for trying to help out your cousin, with this reloading project. But just In case you did not know Weatherby brass , and the dies for it are very expensive.
Barnes 80gr TTSX or even the 100gr TSX shows about the same stability factor. Personally I would go with a Hammer 82gr.
The best option- rebarrel to a fast twist (7.5) barrel so you can run a 115 VLD, 121 HH, and the 131 BJ. I was getting over 3300fps in my Wby with the 131gr, which is leisurely for that cartridge.
The best option- rebarrel to a fast twist (7.5) barrel so you can run a 115 VLD, 121 HH, and the 131 BJ. I was getting over 3300fps in my Wby with the 131gr, which is leisurely for that cartridge.
If you're dead set on loading for this caliber, purchase your dies and some medium to heavy weight bullets and see how they shoot. Try different weights from different vendors too.
