Light, Fast and Devastating By Russell Thornberry


"Battlin’ Bullets - The perennial campfire debate continues. Which hunting projectile is best? Light and fast, or heavy and slow?

P.O. Ackley, the godfather of American ballisticians, forgot more than most of us will ever know about bullet performance. Many years ago, I read his double volume “Handbook for Shooters & Reloaders.” When I turned to his chapter entitled “Killing Power” in Volume I, I fully expected a treatise on why .50-caliber bullets are more deadly than .49-caliber bullets. However, I was amazed to fine something different - something that Ackley called “shockdown power” rather than “knockdown power.”

His premise is simply that the more speed increases, the more shock increases. And when speed passes the threshold of 4,000 feet per second, a whole new dynamic is created - one that cannot be equaled with lesser speed, no matter how large the bullet.
His classic test, which proved his point, was conducted by shooting bullets into ½-inch-thick steel-armor plate from the frontal area of a U.S. military half-track. At a distance of 30 feet, he shot a .270 Win with 100-grain bullets, a .30-06 with military-issue, solid-steel, armor-piercing bullets, and a .220 Swift with a 48-grain bullet.
The results were astounding. The .270 bullet left a shiny spot on the armor plate and did not penetrate at all. Two shots from the .30-06 armor-piercing bullets left shallow craters .070 and .098 inch respectively.

The little .220 Swift bullets consistently burned 3/8-inch diameter holes completely through the ½-inch armor.

The results spoke for themselves. Crossing the threshold of hypervelocity created a dynamic as a result of shock that cannot be achieved any other way.

Ackley’s test was done on armor plate, but how does that translate to performance on the flesh and bone of wild animals? Ackley went on to say that if he had to pick only one rifle for hunting North American game, it would be a .220 Swift.

If, in Ackley’s day, he had had access to the slower-burning powders of today, he would have been able to propel even larger-diameter bullets at “hyperspeed” - bullets traveling 4,000 or more feet per second at the muzzle. I speculate that he would have chosen a larger-caliber, heavier bullet capable of hyperspeed for his choice North American game rifle."

The above brief quoteis exerpted from anarticle appearingin the October 2005 Buckmasters Gun Hunter,reprinted by Barnes Bullets with the author’s permission.

In addition to his penetration tests on steel plate, Ackley cited the results of the use of a .30/'06, a .220 Swift, and an 8X57mm Mauser on wild burros. The .220 Swift made more consistent 1-shot kills on these big, tough "varmints" than either of the larger-caliber rifles which used standard big-game hunting ammunition. (See P 79 of Ackley's handbook for Shooeters and Reloaders, V I. The burros averaged about 600 pounds-probably as tough as an average-sizebull elk.)