6.5 Wildcat Help


Sep 18, 2012
I know this subject has been beat to death, but I need some help/suggestions.

My objectives are:

1. 140 grainers at 3300 fps.
2. Try to use the existing Weatherby Vanguard action I have. (257 WBY)
3. Barrel no longer than 26
4. This will be a deer hunting gun so round count will be low. Barrel life not a concern.

I am strongly considering the 6.5-257 Weatherby, but I am uncertain if I can get the desired velocity. My plan is to send the rifle to Pac-Nor and use a #4 or #5 stainless barrel. All input is appreciated as this is my first go at any wildcat.
You will get very close to 3300 with the 6.5wby. I have one with 24" barrel and I am getting 3250 with 140's. BTW. Vit N560 is the only powder to use as you will get the best velocity and accuracy with it.

You could do a 6.5-300win and get slightly more but not much.
I have never been able to duplicate the 6.5wby with any 264 win mag. My experience has shown that in order to achieve accuracy with the 264 that it has to be loaded at the bottom end of the powder charge while the 6.5 wby really likes to be pushed much like the 7stw. Just my experience.
I don't know anything about the WBYs is it that close?
They are very close. The Weatherby case has a .049" longer neck. The Winchester is .028" longer to the shoulder. You can trim .040" off the neck of a new Weatherby case, expand the neck, and then fire form it in a 264 Winchester chamber.
I know that case capacity of both rounds are about the same, but everyone seems to be getting better velocity out of the 257 Wby case. Why is this? Are they running that much higher pressures in the 6.5-257 Wby compared to the 264 Win?
Any more info on the 6.5-257 Wby?

The good news is that my smith already has a reamer.

I would like to know if 3300 FPS (140 grainers) is possible with the 6.5-257 Wby with a 26 inch tube.
I just ordered a 6.5 WBY from McWhorters.

I asked why 6.5 WBY over .265 win mag. He said the 6.5 WBY has better accuracy at higher speeds than the .264 win mag. In a 26" tube, he said I can expect 3275 fps with a 140 grain VLD.
Based on your velocity desire, I think that is a good choice. If you have an attraction to the Weatherby cartridges, a 6.5-300 Weatherby is comparable to the STW.
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