Quote
Anybody have a recomended load for a 458 mag, shooting a 400 grainer at around 1600-1800 fps. I allready bought some Speer bullets, but not sure of the best powder to use. Thanks.


I'd seat to about 3.00 COL and go with 25-30gr of Unique. Basically loading it as in a big pistol round. Load density over 60%, and good ignition characteristics.

Code
Cartridge          : .458 Win.Mag.
Bullet             : .458, 400, Speer FN 2479
Cartridge O.A.L. L6: 3.000 inch or 76.20 mm
Barrel Length      : 24.0 inch or 609.6 mm
Powder             : Alliant UNIQUE

Predicted data by increasing and decreasing the given charge,
incremented in steps of 3.333% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms

-33.3   51    20.00   1436    1831   28001   1681    100.0    1.901
-30.0   53    21.00   1474    1931   30215   1756    100.0    1.840
-26.7   56    22.00   1512    2031   32492   1831    100.0    1.785
-23.3   59    23.00   1549    2131   34834   1906    100.0    1.734
-20.0   61    24.00   1585    2231   37241   1981    100.0    1.687
-16.7   64    25.00   1620    2332   39714   2055    100.0    1.639
-13.3   66    26.00   1655    2433   42254   2128    100.0    1.595
-10.0   69    27.00   1689    2534   44862   2202    100.0    1.553
-06.7   71    28.00   1723    2635   47540   2274    100.0    1.515
-03.3   74    29.00   1755    2737   50288   2347    100.0    1.479
+00.0   76    30.00   1788    2839   53109   2419    100.0    1.445
+03.3   79    31.00   1820    2941   56004   2490    100.0    1.413
+06.7   82    32.00   1851    3044   58974   2561    100.0    1.383
+10.0   84    33.00   1882    3146   62022   2631    100.0    1.355
+13.3   87    34.00   1913    3250   65149   2701    100.0    1.327
+16.7   89    35.00   1943    3353   68358   2771    100.0    1.302