Yes, great speed and work Sir Ron, another pointer that my load with the 404gr Hammer at 2500 with 2460 has to be extremely low pressure, i cant wait to loose it the first time.
Yes, Sir John is shooting .458 WM+ loads at ~3.37" COL in his standard SAAMI .458 WinMag with standard mag box. ~2500 fps with AA-2230, 3.37" COL, in 24" barrel, in Norma brass. ~2500 fps with AA-2460, 3.48" COL, in 24" barrel, in Winchester, Hornady, or RP brass. Both loads have about same effective case volume, due to brass difference, wee bit larger in the WW/H/RP at 3.480".
Exact velocities and pressures depend on the rifles, of course. Remember Tim Sundles 400-gr TSX Buffalo Bore factory load for .458 WinMag getting 2247 fps in his 22" factory M70 and 2250 fps in his 18" custom M98 with Marquart barrel, and possibly a tighter throat, tighter/smoother rifling, and possibly higher pressures. He does not say much about that. Custom rifle.
My Ruger No. 1 barrel, 24" factory barrel, gave 2336 fps MV (2323 fps 5-yard chrono), 10-shot average with Buffalo Bore 400-gr TSX load. That was with factory load COL of 3.310". My Ruger No. 1 is intermediate in speed to the two rifles of Tim Sundles, correcting for barrel length.
That 400-gr TSX was pulled from factory ammo and loaded to 3.540" COL (last groove crimp). Loaded with 80.0 grains AA-2230 the MV was 2405 fps (2392 fps 5-yard chrono) 5-shot average. That was just about a full case load at longCOL. I SWAG that the Buffalo Bore factory load is with 76.0 grains of AA-2230, compressed at 3.310" COL.
Do not worry about powder compression unless you bulge the case on seating the bullet, or have signs of high pressure on firing, of course. MIB pressure data on that 20" .458 WM and some .458 Lott is pending.
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.
