I have been testing my Weatherby Vanguard 257 Weatherby Magnum with the 100 grain Nosler Ballistic Tip and the ADI propellants AR2213SC (H4831SC in the USA) and AR2217 (H1000 in the USA). The Nosler Ballistic Tip is my benchmark projectile in any calibre.
Given concerns about barrel life in the ferocious 257 Weatherby Magnum I unusually did not do my normal initial testing with Ballistic Tips but rather quickly settled on loads for the 100 grain Nosler Partition and the 110 grain Nosler Accubond. With those loads bedded down, so to speak, and my current hunting of wild dogs and the smaller bodied Chital deer, I saw an opportunity to play around with the Ballistic Tips.
For a 24 inch sporter weight barrelled 257 Weatherby Magnum I was looking for about 1 MOA as my accuracy requirement. With factory ammunition and my reloads I had achieved that and was curious about what I could achieve with the 100 grain Nosler Ballistic tip.
From my initial testing, see graphs below, on my next session at the range I will be focussing on a load of 66.0 grains of AR2213SC, which gave accuracy a smidge under MOA and MV of 3,240 fps. It also appears to be a relatively mild loading as well.
Interesting points to note here are the rapid rise in pressure with the AR2217 loads, and the surprisingly high velocities from the 24 inch barrel. I was obliged to call it quits short of the recommended maximum load of 78.0 grains. In fact, in my rifle, I would say that 75.0 grains of AR2217 would be a maximum. Interestingly, I was able to load right up to the listed maximum of 68.0 grains of AR2213SC without seeing any signs of excessive pressure.