January 04, 2011
By Allan Jones
Going Ballistic!
By Allan Jones
The .30-06 is about as flexible of a cartridge as you are likely to find. Most "super-grade" hunting bullets, such as the Federal Premium Trophy Bonded Tipped shown here, are available in .30-06 factory ammo. |
This is not intended to be one of those "The .30-06 is Still King" columns nor is it a history lesson; those topics have been well-covered by generations of outdoor writers. Like the other columns in the "Ballistician's Notebook" series, it relates my impressions that don't always make it into a reloading manual. You may find it of a confessional nature as well.
In my formative years, I read everything I could lay hands on that dealt with bullet performance on game animals that was written between the two World Wars. That was a time when the world was not yet consumed by magnum-mania. It was very clear that with good shot placement a .24- to .32-caliber bullet of reasonable length and weight moving in the range of 2,400 to 2,700 fps was a solid performer on most deer and elk. My prejudice against the .30-06 blinded me to the fact that a 180-grain bullet in that cartridge was right there. Even today I can't say where my prejudices arose, but I confess them and consider myself "recovered," and I now enjoy two older .30-06 rifles.
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Part of my recovery came in helping a friend ease his teenage daughter into enjoying his semisporterized 1903A3 Springfield. A badly shaped stock meant the veteran rifle would bite with full-power loads if you held it wrong. We started with 120-grain cast bullets over light charges of Unique from an old Lyman manual. The recoil was almost nonexistent. Then we switched to 130-grain jacketed hollowpoints and upped the charge enough to prevent jacketed bullets from sticking. The young lady had great fun shooting them and gained a lot of confidence and skill in spite of the fact that the stock did not fit her. We didn't tell her it didn't fit, and she never asked.
Eventually, we worked up to a reduced load of IMR-3031 under a Speer 150-grain spitzer that clocked 2,400 fps. She said this was as much "kick" as she could enjoy, yet she now had a load that was better than a .30-30 Winchester on our small East Texas whitetails. Throughout this, we were chronographing each load level and saw no inconsistent performance. It struck me that there was significance in this. The .30-06 devoured the light loads with grace, something the larger .30-calibers did not.
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Input Versus Output
My 20+ years at Speer let me see many cartridges from the inside of a pressure barrel. The development procedure allowed us to analyze cartridge performance across the useful range of charge weights with each bullet/propellant combo. Soon it became clear that some cartridges were better than others in producing straight-line behavior in pressure and velocity even when the same propellants were used.
Thirty-caliber cartridges larger than the .30-06 often struggled with producing the straight-line relations we saw with the .30-06. The bigger cases were often "rangier" except at the maximum load. By the time we hit the .300 Weatherby, we were limited to a few propellants that would handle the lighter bullets. When we did the .300 Remington Ultra Mag and the .30-378 Weatherby, we found that publishing serviceable loads meant not showing bullets lighter than 150 grains.
The accompany chart compares propellant usage to velocity gain among common .30-caliber cartridges, using the .30-06 as the baseline. There are more complicated ways to do this study, but for the sake of this column, I settled on using maximum load charges for a bullet weight that all six cartridges handled well--180 grains. All the loads were fired on the latest transducer equipment and standards and achieved 96 percent of the cartridge's maximum average pressure, my standard for a safe cutoff. As some of this data is not yet approved for release, I did not include propellant names. These are real numbers, not the "nominal" velocities from catalogs, and velocities are from a 24-inch industry pressure barrel.
The Remington and Winchester short magnums fared well in this comparison due to their modest capacity increase and higher operating pressure. Statistically, their propellant charge increases posted velocity increases over the .30-06 that are justifiable given the current costs of reloading powders. With the .300 Winchester Magnum, these started to shift in an unfavorable direction. By the time we got to the .300 Ultra Mag, we were using 59 percent more propellant to get a 15 percent gain in speed.
Does this make the big .300 Magnums bad? By no means. It rather means that if this shift in "what goes in" compared to "what comes out" is acceptable to your propellant budget, go for it. To me it says that .300 RUM with a 200-grain or heavier premium hunting bullet would be a heck of a load for long shots on North America's and Africa's largest nondangerous game species. The .30-caliber "megamagnums" are obviously specialized tools, as their extreme capacity favors bullets heavier than 150 grains.
By comparison, the .30-06 is like the most used gadget in your toolbox, one you've used on hundreds of tasks. The .30-06 sits on a tipping point of case capacity that lets it handle the full range of .30-caliber bullets, from 110-grain varmint/plinking bullets to the big 220-grain softpoints, better than anything else. The short mags do great as long as the maximum bullet weight is limited to 180 grains. We tried developing some .300 WSM loads for the most compact 200-grain hunting bullet available, and the velocity increases over the '06 were underwhelming.
Another chart gives a rough look at weights useful in common .30-caliber rifles.
Obviously, the flexibility of the .30-06 favors the handloader, but the nonreloading shooter also benefits from a wide selection of bullet weights and types--including most of the "super-grade" bullets--and a nearly worldwide availability of ammo. Because he can't drive bullets at extreme velocities, a budget-minded .30-06 shooter can usually rely on conventional bullets. The cartridge cannot "over expand" any of the older lead-core hunting bullets, meaning you can control penetration with bullet weight choices alone.
Today, I feel fully recovered from my old prejudices against the .30-06. I commonly recommend it over any magnum to people considering their first big-game rifle. Flexibility is a good thing in any cartridge, especially if you're a reloader. The .30-06 Springfield is about as flexible as you can find.
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.30-Caliber Velocity & Charge Weight Comarison (180-Grain Bullets) |
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Cartridge | Maximum Charge (grs.) | Velocity (fps) | Charge Weight Increase Factor* | Velocity Increase Factor* |
.30-06 Springfield | 59.0 | 2735 | -- | -- |
.300 Rem. SAUM | 68.0 | 2913 | 1.15 | 1.07 |
.300 WSM | 67.0 | 3029 | 1.14 | 1.11 |
.300 Win. Mag. | 81.0 | 3078 | 1.37 | 1.13 |
.300 Weatherby Mag. | 87.0 | 3132 | 1.47 | 1.15 |
.300 Rem. Ultra Mag. | 94.0 | 3146 | 1.59 | 1.15 |
* Relative to .30-06 |