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

Another load tried in the same Ruger Mk II .458 WinMag, about 5 years ago, will be used to illustrate
initial 50-yard shooting and chronographing for 5-shot st. dev., and 3-shot group at 100 yards,
despite a not so terrible crosswind varying between 10 and 20 mph:





An initial fouling shot (#0) chronographed at 5 yards = 2531 fps and went low on target.
The next 5 shots settled down to lower velocity with tiny variance, 5-yard readings:
#1 = 2515 fps
#2 = 2516
#3 = 2514
#4 = 2516
#5 = 2516
Rounded to nearest fps, instrumental mean = 2515 fps, Standard Deviation = 1 fps for 5 shots.
+12 fps for BC = 0.372, 5-yard correction, gives MV = 2527 fps, in 25" Shilen barrel.
Estimated 24" Shilen barrel velocity = 2512 fps.

Call it a nominal 2500 fps MV load for the generic 24"-barreled .458 WinMag,
and about 2350 fps MV for 18"-barreled .458 WinMag.



First 3-shot group at 100 yards had variable winds:



Second 3-shot group at 100 yards had less variable wind, closer to steady wind:



A total of 18 HV bullets were used for this exercise.
Those Hardcast-Hi-Vel bullets will save some money in substituting for the HV and Hammer bullets
with same powder charges in practice loads for varmint shooting.
Whatever a .223 Wylde can do, so can a .458 WinMag.
Same powders work well in both with slightly different charge weights.