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Ballistics

That Elusive and Maddening Quality Called Accuracy

by G&A Staff   |  February 1st, 2018   |   0
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A no-holds-barred, Al Biesen custom .270 Winchester, built on an FN Deluxe action, probably in the 1970s, was accuracy state-of-the-art then, and as a big-game rifle it can hold its own with any rifle of today.

Everyone has his own definition of accuracy, but on one thing we all agree: Every rifle is a law unto itself. What shoots well in one rifle may or may not shoot well in another.

Although the average factory rifle today, paired with premium factory ammunition, is vastly more accurate than it was even 20 years ago, for the absolute, very best, gilt-edged accuracy in any rifle, you must develop an accurate handload.

Undoubtedly, manufacturers today have the essential elements of accurate rifles down pat, to the point where they can produce some outstanding factory products at a low price. Ruger and Savage are good examples. Even so, they won’t all shoot well with every load, and all of them can be improved with handloads. Granted, sometimes the factory/factory combination is so good that handloading for improvement is hardly worthwhile, but that’s a personal judgment.

A Case in Point

Having said all that, let me now share a tale of a rifle that proves the point. Last year, I lucked into a custom .270 Winchester built by the legendary Al Biesen on an FN Deluxe action, probably in the 1970s. It is beautifully inletted, with the action partly glass bedded. It has a tight chamber with almost no freebore. In fact, with the Nosler 130-grain Partition (one of my all-time favorite bullets), it has no freebore at all. Seated to the SAAMI maximum cartridge length of 3.34 inches, the bullet just brushes the rifling, and seated to that depth, the base of the bullet is exactly even with the base of the neck. These are all ballistic virtues that we know promote consistency and accuracy.

I got the formula for a load from Tom Turpin, a .270 Win. lover of long standing, that he says delivers fine accuracy with any good 130-grain bullet. The load is 59.5 grains of H4831, long known as one of the finest powders for the .270 Win. As an experiment, I put together some rounds loaded with the Partition, as well as some with the Swift Scirocco II and the Sierra GameKing Spitzer boattail. The latter two do not fit the chamber specs mentioned above quite as well as the Partition, but they’re close.

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Although the Sierra 130-grain GameKing had the lowest vel- ocity, and its overall group measured 1.40 inches, its 0.77-inch four-shot cluster suggests that increasing the velocity a little might result in gilt-edged groups.

At the range, the Partition load was dreadful. Velocity wasn’t bad, at 3,020 fps, but its five-shot group was evenly spread out 3 full inches, side to side. The Scirocco II bullet won the velocity contest, at 3,060 fps, and also delivered the best accuracy overall with a 1.25-inch five-shot group. The Sierra bullet was the slowest at 2,998 fps but put four bullets into a tight cluster of 0.77 inch with one flyer expanding the group to 1.40 inches.

Let me hasten to say that I love Partition bullets, firmly believe they are among the most accurate bullets made, and have shot some of my all-time best groups with them, in several different calibers. From my chamber measurements, it looked to me as if Biesen fashioned this rifle specifically for the Partition, but apparently not. At least not at that velocity. I will try different powder charges and different powders before I give up on them. There is no reason that they shouldn’t shoot like a house afire.

Meanwhile, the other two are excellent hunting bullets, and a little variation up and down may tighten those groups even further.

Group size aside, this old masterpiece of a custom rifle behaved to perfection, moving groups up and down like clockwork as the velocity varied, and putting them all in the same relative position on the target. There was not a hint of vertical stringing and no discernible changes as the barrel heated up. In other words, all perfect—except for that maddening 3-inch group!

But that’s the accuracy game with hunting rifles. Each one is a law unto itself, and you can never take anything for granted.

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