Home Forums Hunting & Shooting Express Rifles and Big Bores Only The great 458 Winchester. Everyone should own one at least once

Thanks for that tip on the testimony, will find it and watch it, Sir Bob.

The 404-gr/.458 Shock Hammer has struck paper with my starting load.

I got out an hour before sundown on Thursday 2-10-2022 and turned on the auxillary chrono lights.
Fired bullet #1 to verify on paper by bore-sighting at 50-yard target.
Then an elevation adjustment of scope and shot #2 was fired.
Then a windage adjustment of scope and shot #3 was fired.
Third shot was an inch away from spot-on at 50 yards.
With adequate fouling and the rifle and scope seeming to be functioning properly,
three more shots were fired for 50-yard group and 5-yard chronograph.
48 degrees F
Barrel: 25"-long Shilen, 1:14" twist, stainless, No. 5 sporter contour.
CZ 550 Magnum with NightForce SHV 3-10x42mm in Burris X-Tac Low rings on 2-piece Picatinny bases.
Hornady Brass
F-215 primer
COL = 3.480" (I relented on 3.380" COL due to discovering powder compression at that COL)
Seating depth = 0.460"
80.0 grains of AA-2230
Instrumental velocities in fps: 2468, 2467, 2471
Mean = 2468.7 fps
for BC = 0.419 G1, add 10.3 fps to correct to MV = 2479 fps
Group at 50-yards was a cloverleaf of 0.430" on centers, equivalent to 0.82 MOA.

80.0 grains of AA-2230 is 100% fill or minimally compressed with no drop tube.
I will use a drop tube and add more powder at same 3.480" COL.
81.0 grains ought to be over 2500 fps.

The PDR bands might be requiring more powder to get the pressure up.
Just conserving expensive bullets here.