Winchester's Big Bore Powerful .357 Magnum for Hunting or Defense

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Not long ago, Winchester introduced a new line of handgun ammunition called Big Bore. It is intended for hunting and personal protection. Calibers are .357 Magnum, 10mm Auto, .44 Magnum, and .45 Colt. They feature a semijacketed hollowpoint bullet that provides optimal expansion and deep penetration in big game. I tested the .357 Magnum load for velocity and accuracy. Its ballistics are a 158-grain jacketed bullet at 1,460 fps. Winchester’s catalog shows this speed from a 6.0-inch vented barrel, but the ammunition box shows this speed from an 8.5-inch vented barrel. I guess someone at Winchester couldn’t make up their mind. That happens to me, too.

The barrel lengths I had available were 4.0 and 7.0 inches—both are S&W Model 686s. In the 4.0-inch barrel, the loading averaged 1,156 fps, and in the 7.0-inch barrel, it averaged 1,327 fps.  Based on my chronograph readings, it looks like Winchester’s advertised speed is from an 8.5-inch barrel. Accuracy was assessed at 25 yards with the guns mounted in a Ransom Rest. The 4.0-inch revolver produced an average five-shot group size of 3.22 inches and a 20-round group of 4.56 inches. My 7.0-inch gun loved this round, producing an average five-shot group of 1.24 inches, and it kept all 20 rounds in just 1.47 inches. That’s a third of the group size of the 4.0-inch gun. (The ammo was all from the same lot number.) If you’re looking for a potent hunting or defense round that offers deep penetration, check out Winchester’s Big Bore line.