Puzzling Over Performance


Early-bullets-8x57-030316George Santayana is credited with the observation that those who do not remember history are doomed to repeat it. Put another way, those who do not remember the snake oil of 50 years ago are more than likely to buy it today, if the seller is loud enough, and can back up his claims with a glossy website and some DVDs.

Anyone who ever worked in television knows that video fakery is a way of life, and nothing can be cooked up easier than a DVD. All you need is 50 bucks, a computer and a compliant geek.

For more than a century, bullet makers have been looking for the perfect hunting bullet. Along about 1910, they thought they at least had the goal pretty well defined: A good soft-nosed bullet should expand readily at a reasonable range of striking velocities, open into a nice mushroom, and still hold together to retain maximum weight, and hence penetration power.

Bullet Performance
The Nosler Partition Bullet

Achieving that was a bit more difficult, but for Americans it achieved working reality with the Nosler Partition, introduced in 1949. The Nosler copied the RWS H-mantle, which had proven itself in Europe and Africa. The front half expanded readily, a solid copper belt in the middle stopped expansion just short of the halfway mark, and the base continued to penetrate. Generally, it retained about 60 percent of its weight. We would have preferred it retain more, but soft and frangible lead was the price we had to pay for dependable expansion.

Since then, a number of things have happened. One is the completely unreasoning fear of lead in bullets. Another is the determination to bond the lead core to the copper jacket in some way, to promote greater weight retention. Generally speaking, any attempt to strengthen one quality will usually compromise one or more other qualities in a bullet.

By 2000, with Trophy Bonded, Swift and Woodleigh all offering bonded bullets in one shape or another, and all delivering weight retention better than 90 percent, the problem was pretty much solved. Then along came the idea that lead is a deadly poison, and that homogenous bullets made of one substance (copper alloys, usually) are — or can be — more accurate.

Early attempts at making any kind of a solid copper alloy expand reliably at a wide range of velocities, and stay together, were haphazard to say the least. Pure copper is hard to work with and gums up bores at high velocity, while alloys become varying degrees of brittle. When they expand, the little petals break off.

Bullet performance
Example of terminal performance of Swift’s Scirocco bullet in .308

The answer? Turn a vice into a virtue, and claim that the petals are supposed to break off. They are designed to break off. That breaking off, as the bullet penetrates, sends them off in all directions, penetrating like shrapnel. That this leaves a stump that continues to penetrate better than it would if the petals had stayed on, delving deep into the animal’s innards.

Here we run into an unfortunate fact of physics: Penetration is largely determined by weight. A heavier slug penetrates deeper than a lighter one. Therefore, the stump of a bullet, retaining 50 or 60 percent of the original weight, will not penetrate as well. What’s more, a detached petal has the aerodynamic qualities of a toenail clipping, and penetrates nowhere at all. They are typically found in, or extremely close to, the wound channel.

When you step back and look at it, what we have accomplished is duplicating the terminal performance of the Nosler Partition, but without the lead. Having spent almost 30 years extolling the virtues of the Nosler Partition, I am not about to complain about a bullet that duplicates its performance, with or without lead. Dead is dead.

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One thought on “Puzzling Over Performance”

  1. So controlled defragmentation bullets is better then? Much easier to hit a nail through wood then a coin?
    What was the point of this puzzle about performance?

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