6mmx257 weatherby Mag.

henbe

I have a 6mm x 257 weatherby mag, all reloading equipment, except for the recipes for the powder measure and what grain/type of bullet works the best can anyonr help me?

fishmasty

I would imagine it would be the same as a 240 weatherby mag.

http://data.hodgdon.com/cartridge_load.asp

sandwarrior

henbe,

Two different cases, the .240 WBY and the 6mm-.257 WBY. The former is a much smaller case. The latter is the same case as used on the .257 (0bviously) and .270/7mm Wby.

I don't have load information worked up but where to start would be midrange of the 6mm-.284 (a close but smaller case). A good place for that is www.reloadersnest.com It'll be anemic at first. You will then need to work up to where your rifle is shooting and performing it's best without serious pressure signs. You have picked a doozy to find information for.

Another place to find a starting load for this is Quickload. Either buy the software or find someone with it. Well worth it if you go off the beaten track of cartridges to load for.

Also, you will need to find the twist of the barrel to determine which bullet will probably work best in your rifle. I'm going to say right up front that with speeds like what you're intending, Nosler is going to be the better bullet as it's tough enough to handle it.

stevecrea

The .257 Weatherby case is very large relative to a 6mm bore. Accordingly, I would think that it would tend to perform relatively better with the heavier bullets in 6mm, and with very slow burning powders. For example, 100 grains and up, and Hodgdon 4831 and slower.

I have a 240 Weatherby, and it likes slower burning powders such as 4350 and 4831. Your .257 case is much larger, and should like even slower powders, long barrels, etc.

nononsense

henbe,

Welcome to the Gunbroker Forums!

That's a little more case than is needed for the tiny little 6mm bore. It's very close to the older .244 H&H cartridge.

The .257 Weatherby case has 84 grains of capacity.

The .240 Weatherby has 64 grains of capacity.

What you haven't told us is how long the barrel is and what the twist rate is. These two pieces of data will help us guide you through the reloading process for cartridges such as this.

As has been mentioned, longer barrels, slower powder and the heaviest bullets supported by the twist rate will be the best bet. The only drawback that I see is that with standard barrel lengths and hunting bullets you will only be able to match the velocities attainable with the .240 Weatherby and 20 grains less powder...

Tell us some more information and we'll see what we can do to help.

Best.