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

Very good. Norma brass was 4.7 grains greater in gross water (99.3 gr) than Hornady (94.6 gr).
Increasing the COL of the .458 WM+ from 3.380" to 3.480" will add 4.2 grains of water gross.
So a 3.480" COL with Hornady brass is very like a 3.380" COL with Norma brass.


Using Norma brass and the 404-gr SH with AA-2230, I found that increasing the COL from 3.38" to 3.48"
caused a velocity loss of -63 fps.
Adding 4 more grains of AA-2230 to the 3.480" COL boosted that reduced MV by +120 fps.

Seems that you need to add about 2 grains of powder for each 0.1" of extra COL to keep same MV/pressure.
Likewise, use of Hornady brass case requires about 2 grains less powder than a Norma brass case
at same COL for both, for about same MV.

I believe the 404-gr Shock Hammer benchmark-BENCHMARK load ought to be with COL set at 3.340", wherever the crimp may fall.
And it ought to use the more standard 94-ish-grains brass instead of the 99-ish-grains Norma brass.
This should be compared to the "Woodleigh Bullets Loading Manual" results for 400-gr PPSN with the crimp in the factory cannelure:
78.0 grains (compressed) Benchmark/Benchmark 2 for 2340 fps MV.
Seems kind of slow for the manual data.
Like what Sir Russ found with his rifle and 450-gr HYDRO.

My listing, again, of findings for brass makes,
once-fired, not resized,
and mathematically corrected to 2.500" brass length for gross water capacity:

Norma: 99.3 grains
W-W Super (post 1996): 94.9
R-P: 94.8
Hornady: 94.6
Federal: 94.6
Federal Nickle-plated: 94.4
Peterson Wildcat tube: 93.8

I think I will save the Peterson Wildcat tube for the .458 Watts-Winchester 2.7": 102.1 grains H2O gross.
MAP for the .458 WW will be 65,000 fps, same as the .416 RemMag.
So it will really leave the .458 Lott in the rear view mirror,
with same loads as the .458 WM+ that uses a SAAMI chamber.