25/7mm Mag data?

Sorry for the confusion. It is a .25-7mm mag., that's a 7mm Remington Magnum necked down to .257 caliber. It's a wildcat cartridge. It should be very accurate (with the right load), scary fast, and with the new, high BC bullets out there now, should fit my Dad's desire for a light recoiling semi-long to long range rifle for coyotes and pronghorns.

The problem is, I don't have the time to start loading/chronographing from scratch, and was hoping someone else out there had played around with this one.

Sounds very similar to Weatherby's 257 Mag. You probably don't have the Weatherby freebore in your rifle but using 257 Wthby starting loads should be a safe starting point.
The 257 Weatherby and the 7mm Rem Mag both have a case capacity of 80 to 81 grains of h2o, so it you used 257 Weatherby data and reduced by 10% to start, you should be safe.
Thank you very much!!! I don't know why I didn't think of that...I used to have a 257 Wby! I guess I deserve a "DUH" for this question.

Thanks again!
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