Boy, it sure his hard to believe just people have come to the wrong conclusions on the 257 Weatherby!
The first 257 Weatherby that I shot with zero freebore was on a Mauser 98 Action, in a Brown precision stock, 26" Douglas barrel with a muzzle break. My first shot, I popped a crow sitting on the top of a cactus at 300 yards, and I saw the bullet hit the crow, the gun barely recoiled.
My hunting partner that had the custom 257 W was a gunsmith in San Diego and had built many of the 257 Weatherby's for customers over the years that were throated with zero freebore. His load was a nosler Ballistic tip going 3800 fps, boy did it turn a coyote inside out! We shot crows and coyotes all weekend with the rifle, and on Monday, I ordered a Match reamer with minimum spec dimensions, zero freebore. Prior to ordering the reamer, I ran some new 7 Mag Winchester brand of brass into the 257 Weatherby full length sizing die, and the double radius on the shoulder was perfectly formed. So, I sent the re-formed brass off to Pacific Precision, and he ground a reamer off the short neck 7 Mag brass that had been necked down to 257 Weatherby.
My first barrel chambered with the reamer was a3 Groove Pac Nor 26" Select Match, 10" twist, fluted #6 taper with a muzzle break. On the first trip to the range, I worked up a load (following my gunsmith's instructions) and within 15 shots, I had 3 shot groups in the low .300 range with a velocity of the 100g Nosler Ballistic tip at 3850 fps. I next tried the 100g Partition and accuracy was 1/2" at the 3850 fps.
I next tried the Sierra 100g Spt BT and the 100g Sierra Match bullets, and they shaved about .040 off the group size of the 100g Nosler Ballistic tips getting 3 shot groups down in the two's at 3850 fps.
You can say what you will, but since I had my 257 Rifles built, I know of more than a dozen done the same way by different gunsmiths all over the country.
I sight in my rifle 1/2" high at 200 yards and I am 4" low at 300. A deer's legs fly out from under them when hit with this kind of load at 300 yards.
Since you start off with zero freebore, you get great barrel life out of this round as a hunting round. I have 237 rounds through my barrel now and the leade has grown about .035 in the Pac Nor 3 groove Super match barrel. Pac Nor's Rockwell Hardness is somewhat harder and a different kind of material than some of the conventional barrels.
Those of you wanting to try a custom 257 Weatherby, I strongly urge you to do so on what ever action that you have. Send me a PM if I can be of any help.