The Vanguard averaged 3357 fps with Norma MRP behind the 115-grain Nosler Partition, which compares quite favorably with the 3384 fps I got with factory ammo loaded with the Nosler 115-grain Ballistic Tip. The exception I mentioned earlier is the Nosler 120-grain Partition; my fastest handload averaged 3326 fps, which was almost exactly 100 fps slower than the factory load with the same bullet. In addition to being faster than any of my handloads, it was 25 fps faster than its factory velocity rating.

Plenty of excellent .25-caliber bullets are available for handloading the .257 Wby., but slow-burning powders are required.

Handloading the .257 Weatherby is rather straightforward with no pitfalls I am aware of. Like any cartridge operating at high chamber pressures, its case has a tendency to stretch and should be trimmed back to 2.540 inches as required. As primers go, you could probably get by with the standard-force variety with some powders, but I prefer to keep life simple by using nothing but magnum primers in this cartridge. Weatherby factory ammo is loaded with the Federal 215, and the relatively new Gold Medal Match version of that primer is what I now use with great satisfaction.

Then we have the matter of bulletseating depth. For many years, Weatherby rifles chambered for all calibers except the .240 Magnum had chambers with 3/4 inch of freebore, but it was shortened to 3/8 inch during the late 1960s. Overall cartridge lengths for .257 Weatherby factory ammunition is usually close to the following:

• Hornady 87-grain SP, 3.090 inches;
• Hornady 100-grain SP, 3.145 inches;
• Barnes 115-grain XFB, 3.150 inches;
• Nosler 115-gr. Ballistic Tip, 3.160 inches;
• Nosler 120-grain Partition, 3.160 inches.

I have tried seating bullets out of cases a great deal farther than those lengths in order to reduce freetravel in the relatively long chamber throats of Weatherby rifles, but quite often accuracy proves to be worse than when I stick closer to the overall lengths of factory ammo. In the handloads I shot in a Vanguard for this project, I seated the Hornady 75-grain V-Max to an overall length of 3.20 inches, and all other bullets were seated to 3.25 inches.

When developing loads for a rifle in .257 Weatherby Magnum, don't forget to allow the barrel to cool down after each group is fired. Ambient temperature was in the high 90s when I shot the loads listed in my chart, and after firing only three rounds the barrel would become too hot to touch.

Allowing the barrel of a rifle in this caliber to heat up excessively during sustained firing will shorten its useful life considerably whereas properly cared for, it will last for many hundreds of rounds. (Roy Weatherby once told me that of the many rifles he had sold in .257 Magnum, not a single one had ever been returned to him for replacement of its barrel.) To speed up my velocity/accuracy testing, I cooled down the barrel of the Vanguard between groups by rubbing its exterior surface with ice cubes I had taken to the range in a cooler. This is one of the advantages to having a rifle with a synthetic stock--you don't worry about getting it wet.