Hot Stuff
Col. Charles Askins tested one of the very early .357 Atomic sixguns. “Bill Wilson, chief guru at Great Western, contributed a 71/2″ .357 for the cartridge he calls the ‘Atomic’… The first six shots with the Great Western .357 Atomic indicated excessive headspace. Examination of the cartridges, not those provided by Bill Wilson but standard Western Metal Piercing stuff, showed the primers were almost pushed out of the primer pockets. The indentation of the firing pin had been completely ironed out, indelible evidence of excessive headspace. I did not fire the GW after this showing.” This problem was soon corrected and is not exhibited in my pair of .357 Atomic sixguns.
Today’s Alliant #2400 seems to be slightly hotter than the original from Hercules. Both friend Brian Pearce and I have concluded charges should be cut about six percent, which means 15.0 grains is about as high as we should go with today’s powder. For many years I used 15.5 grains of Hercules #2400 with the 158-grain Thompson GC bullet. Now I am older, and so are my sixguns, and I rarely top out over 14.0 grains.
However way back in the 20th century I did do some testing with the 16.0- grain Hercules #2400 under the RCBS #38-150 KT bullet which is very close to the original design from the 1930s by Phil Sharpe used in the Winchester factory loads of the time. Before I publish my results here, I would say do not use this load with current #2400. Highest muzzle velocity from an 8″ Colt Python was 1,638 fps. Others in chronological order were Dan Wesson 10″, 1,585 fps; S&W 83/8″ .357 Magnum, 1,493 fps; 6″ Dan Wesson, 1,418 fps and a 45/8″ Ruger Flat-Top Old Model at 1,402 fps.
Before the doors closed on Great Western in 1964, at least a baker’s dozen calibers had been listed. In addition to the above standard chamberings, others included .22 Magnum, .44 Magnum, .44-40, .38-40, .22 Hornet and .30 Carbine, all of which are extremely rare. Just because the caliber was listed does not mean one can find a Great Western so chambered.
The .357 Atomic lasted about two years and continues to be shrouded in myths and mystery. When one considers the .357 Magnum and .44 Magnum have been around for 85 and 65 years respectfully, and are still surrounded by myths, it isn’t very likely the mystery of the .357 Atomic will ever disappear.
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