Anything .458 caliber is cool IMHO, from .45-70 and SOCOM to .460 G&A and Weatherby. Always interesting to hear how which bullet at what MV did at what range to what critter.
IMR-4451: I have not tried it, but might have put some in the powder locker. Or was that IMR-4166 ? Would have to dig to see. IIRC, IMR-4451 burn rate is a tad slower than IMR-4350. and IMR-4166 is a tad slower than IMR-4895, but faster than IMR-4064. But both are Enduron powders that cut copper fouling and have good temperature insensitivity.
IMR-8208 XBR is slightly faster than IMR-4895, super-short-grained, tops in temperature insensitivity, and I can vouch for a lot of good load data with that in .458 B&M, .458 WinMag, and .458 Lott, pressure tested and chronographed by Michael McCourry in South Carolina. That would be my next choice to test in the .458/.416 Ruger.
As suggested by Sir Bevan: Another good one to consider is CFE 223, ball powder, good for +2200 fps in the .458 WinMag with 500-grainers, at 3.340" COL or less and 60,000 psi or less. Ought to be great with heavy bullets in the .458/.416 Ruger.
Ron aka "Rip" for Riflecrank Internationale Permanente NRA Life Benefactor and Beneficiary .458 Winchester Magnum, Magnanimous in Victory THE WALKING DEAD does so remind me of Democrap voters. Donkeypox.
