The Wildcat 156 grain ULD is the best wind bucking bullet that I have used so far. However, apart from the 100 grain .224, I have not yet used Richard's other heavy ULD bullets in other calibres, so I am in no position to claim it is the best.
Testing of the 156 grain bullet in the 257W (26 inch barrel)with Norma brass only produced 2,880 to 2,900 fps. This was disappointing as earlier chronographing of this bullet in my 25/06AI (24 inch barrel) produced 2,830 fps. So if you take into account the extra 2 inches of barrel, the 257W only produced about an extra 20 fps from the extra 19 grains case capacity.
My fears that the Norma brass was soft, appear to be correct, as the Remington 300 Winchester Magnum brass when necked down to 257W is consistently producing between 2950 and 2970 fps with 1 grain less powder. Once I have fired at least 6 shots with each 300WM case, I will feel confident that the pressures I am using to produce 2950 fps are sustainable.
Several weeks ago, I tested the 142 grain Wildcat ULD in my 257W for the first time. Unfortunately this bullet (J4 jacket) came apart at velocities ranging from 3,050 to about 3,150, which surprised me as Kirby had earlier predicted that I should get to 3250 without problems, which was based on his experience using an 8 twist.
However, after doing the maths, 3,050 fps in a 7 twist produces 313,714 rpm, while 3,300 fps in an 8 twist only produces 297,000 rpm, so I guess my results with the 142 are predictable.
I hope to test the 125 grain ULD (J4 jacket) in the next 2 weeks, and it will be interesting to see if it holds together, and what velocities are achieved.
I hasten to add that the 156 grain ULD is a tough bullet, has delivered excellent accuracy, and has not shown even a hint of coming apart. Hope the above helps. Brian.
