The .308 Winchester
It’s One Of The Most Accurate
Rifle Cartridges Ever.
The .308 Winchester is the civilian version of the 7.62x51mm NATO, a round derived by the US military from the .300 Savage to approximate the World War II ballistics of the .30-06. Introduced commercially in 1952, 3 years before the 7.62×51, the .308 became a standard chambering in rifles around the world.
Any military round has a commercial advantage, especially those adopted by the US, but the .308 and 7.62×51 aren’t exactly the same round. The differences aren’t as large as those between the .223 Remington and 5.56mm NATO, but they can cause problems in a few rifles. The chambers of 7.62×51 rifles are often generous, especially in autoloaders for easier function, and military brass is usually thicker. As result, some commercial .308 ammo may stretch or even separate when fired in some 7.62×51 chambers, and some 7.62×51 ammo may not chamber in some .308 rifles. If you own a 7.62×51 rifle and want to use .308 ammo, it’s sensible to have a gunsmith check the headspace to make sure it matches .308 specifications.
Otherwise, the only real difference between the two rounds occurs in handloading: Maximum .308 loads sometimes develop too-high pressures when fired in heavier military brass. The loads tested for this column in the Ruger American all used .308 data, and were fired in commercial Remington brass averaging 185 grains in weight. They’re a grain or two under the listed maximum, so shouldn’t be too hot with military brass, though velocities will probably be higher than in the Ruger. If using similar-weight commercial brass, they can be safely increased slightly.
There are other reasons for the .308’s popularity. It recoils relatively modestly, and more types of bullets are available in .30 than any other caliber. Also, while some shooters argue “inherently accurate” cartridges don’t exist, if they exist .308 would be on the short list. It’s been used in just about every target discipline, even short-range benchrest shooting, and shoots accurately even in factory hunting rifles.
My first “real” big-game rifle (as opposed to a Mosin-Nagant sporterized with a hacksaw) was a Savage 99 EG in .308. Even in the hands of a 13-year-old it grouped Winchester factory ammo into a little over an inch at 100 yards.
I’ve fooled around with a number of .308’s since, including a couple of other lever-actions, a Remington 7600 pump and a Merkel break-action single shot. All 3-shot groups at 100 yards, whether with factory ammo or handloads, have averaged 1.18 inches, and bolt-actions averaged under an inch.
While the .308 will shoot well with a lot of powders, Hodgdon Varget (above) has become a standard.
The most accurate .308 John’s ever fired is one of the reproductions of Chuck Mawhinney’s M40 sniper
rifles. That is a 5-shot group (below) at 100 yards.
The most accurate bolt was one of the 50 reproduction M40 rifles commissioned a couple years ago by Chuck Mawhinney, the Marine sniper with the highest number of confirmed kills in Vietnam. They’re faithful to the original M40 in every detail, down to the clip-loading slot on top of the Remington 700 action, useless because of the fixed Redfield mount. The green-anodized Redfield scope is a reproduction provided by Leupold, now the owner of the Redfield name.
Mawhinney personally breaks in every rifle with Black Hills’ 175-grain boattail hollowpoint match load. The rifle I shot, serial number 029, averaged under 0.5 inch with the Black Hills ammo—for five shots at 100 yards—not three. Chuck says some of the rifles shoot even better, though I suspect 029 may have shot better with him behind the trigger.
The three real lightweight .308’s I’ve shot have been my Merkel and a Sako 75, both right at 7 pounds scoped, plus my wife Eileen’s Kilimanjaro custom on a Kimber action, a wispy 6.5 pounds even with a fancy walnut stock and 3.5-10×40 Leupold. Three-shot groups from all three rifles average under 0.75 inch at 100 yards, so yes, even flyweight .308’s can shoot very well—and not damage the shooter in the process.
Somebody once joked the .308 would probably shoot well when loaded with double-based horse manure, but even though a lot of powders work, an awful lot of shooters use Hodgdon Varget, one of Hodgdon’s Extremes. Varget not only produces good velocities with 150- to 180-grain bullets, but also produces the same velocities in a wide range of temperatures.
As a result it’s easy for .308 handloaders to get stuck in a Varget rut, but several other powders of about the same burning rate are also very temperature-resistant, including Alliant Reloder 15 and AR-Comp, and Ramshot TAC. All are worth trying, and may outperform Varget in some rifles. (However, while loading ammo for this column I realized I’d only tried Varget with 150- to 165-grain bullets, so stuck some under 180-grain Nosler Ballistic Tips. The result? The best accuracy of the test.)
Data for another new powder, Hodgdon CFE 223, shows high velocities for heavier bullets in the .308, so was tried with 200-grain bullets. The big theoretical advantage of CFE 223 is reduced copper fouling, due to a de-coppering agent in the powder. This isn’t exactly new technology, however, since de-coppering has been a feature of military ammunition for many years.
The de-coppering agents most frequently used are bismuth, lead and tin. On firing they form a brittle amalgam with the copper in the bore, and the next shot blows out most of the copper. Artillery ammo often features foil or wire on top of the powder charge, but that isn’t practical for small-arms ammo. Instead, the agent is incorporated into the granules in several older ball powders, plus the newer Ramshot TAC, a Belgian powder originally designed for use in the 5.56 and 7.62×51 NATO rounds.
An almost-new Ruger American rifle was used to test newer powders. Such an “affordable” rifle might seem an odd choice, but Ruger makes some of the smoothest factory barrels on US rifles these days.
The only previous shooting I’d done with the American was at the FTW Ranch in Texas during a shooting school and axis deer hunt. At the end of the shoot around 150 rounds had gone down the new barrel without cleaning. The rifle was still hitting gongs out to 1,000 yards, and when finally cleaned there was relatively little copper in the bore. While checking the scope’s zero before testing the handloads, I used the same Black Hills 175-grain match ammo favored by Chuck Mawhinney, and the first 3-shot group on paper at 100 yards measured 0.34 inch.
I’d happily carry a .308 for 98 percent of the world’s big-game hunting, and it’s commonly used as a medium-range sniping round in many countries, not just the United States. It just plain works, and will continue to work until there’s some unforeseeable revolution in rifles and ammunition.
By John Barsness
Four of John Barsness’s nine books are on firearms and shooting. His latest, Rifle Trouble-Shooting and Handloading, was published in 2012 by Deep Creek Press, and is available through www.riflesandrecipes.com, P.O. Box 579, Townsend, MT 59644, (406) 521-0273.
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