TEXAS GUNS by Steve LaMascus

March 25, 2017
March 25, 2017

The Magnum .30s

T he first .30 Caliber was an American invention.

In 1913, firearms inventor and designer, Charles Newton, of .250-3000 Savage fame, developed a large-cased, non-belted, .30 caliber for gunsmith Fred Adolph. He initially called it the .30 Adolph Express.

Later, when Newton brought out his own line of rifles, he chambered them for, among others, his .30 magnum and called it the .30 Newton. By modern standards the .30 Newton wasn’t much, but in those days before WWI it was a red-hot round, pushing a 180-grain bullet to 2,860 feet per second—200 feet per second more than the .30-06 could then manage. That’s more than the current difference between the .30-06 and .300 Winchester Magnum.

In 1925, Holland and Holland introduced the Super .30. That same year Winchester began loading the big .30 caliber round, calling it the .300 H&H Magnum. This cartridge really kicked off the .300 magnum craze, and it was the predecessor of practically all the .300 magnums for a half-century.

The .300 H&H is a long, gently sloping cartridge that is prone to case stretching and other maladies that reloaders avoid. It will not match the other .300 magnums in velocity, and is not very popular today.

In 1944, California gun crank, Roy Weatherby, produced a wildcat based on the .300 H&H—the mighty .300 Weatherby. The .300 Weatherby Magnum is nothing more than a greatly blown out .300 H&H.

In forming the .300 Weatherby, Roy managed to increase performance by a huge margin. The big Weatherby cartridge was the most powerful .300 magnum round for many years. It still runs in the same fast company as the .300 RUM and .30/378 Weatherby. The two latter cartridges only manage to best the .300 WM by a hundred feet per second with 180-grain bullets, and only then by burning as much as 30 more grains of powder.

For decades, almost every winner of the prestigious Weatherby Award depended on the .300 Weatherby for hunting a huge variety of big game in far-away and exotic places. Even today the .300 Weatherby is one of the most popular cartridges for globe-trotting hunters. It is, in my humble opinion, the best of the .300 magnums, being of maximum powder capacity for a .30 caliber bore.

When Winchester began bringing out their line of short magnums based on the .458 Winchester Magnum case, they missed the boat by not developing a .30 magnum on the same cartridge case. They only offered the .338 Winchester, .264 Winchester and 7mm Remington Magnums.

However, Norma of Sweden beat them to the draw by introducing their .308 Norma Magnum. This cartridge was introduced specifically for the American trade in 1960. It is probably what the .300 Winchester Magnum would have been had Norma not gotten there first.

The .308 Norma Magnum is a fine cartridge, pushing a 180-grain bullet to more than 3,000 feet per second. Being almost identical to the wildcat .30-338, it was becoming quite popular until Winchester introduced their own .300, the .300 Winchester Magnum.

Since Norma used the Winchester short magnum case (This was long before the WSM series.) for their .300, Winchester had to develop a different design. They decided to use a case that was short enough to fit in a standard .30-06 length action, but with greater powder capacity.

The .300 Winchester Magnum is longer from base to shoulder than the other short magnums, but in order to fit the standard actions, has a shorter neck. This design is lacking in some ways. Because it is chambered in standard length actions, it does not allow long, heavy bullets to be seated out far enough not to intrude on the powder space, and its short neck does not hold those same long bullets as firmly as a longer neck would.

This makes the .300 Win. Mag. less desirable for reloaders. Still, it is a fine cartridge that has greater powder capacity than the other short magnums, producing slightly higher velocities, especially with carefully crafted handloads. It is, today, the most popular .300 magnum in America.

The .300 Remington Ultra Magnum is Remington’s entry into the mega-magnum market place. It is a huge case, using more than 100 grains of slow burning powder to produce 3,300 fps with 180-grain bullets. The downside is that it kicks like a howitzer and burns up barrels in a big hurry.

It is only a bit more powerful than the .300 Weatherby and is not as well balanced in most ballistic ways. It takes a minimum of a 26-inch barrel to use all that powder, and a 28-inch barrel would be better. Its only advantage is that it is available in factory Remington rifles.

The .30-378 Weatherby is a monster from anyone’s point of view—more so than the .300 RUM. It is badly overbore capacity, uses huge amounts of powder, but gets very little additional velocity in the heavier bullet weights, which are the only ones that should be used in this leviathan.

In the 9th Edition Hornady Handbook of Cartridge Reloading, it shows 3,300 fps with a 180-grain bullet, stoked with 117 grains of ultra-slow burning powder. It was, according to Cartridges of the World, developed for 1,000-yard benchrest competition. That is where it should be left. The hunter would be better served with a .300 Winchester or .300 Weatherby. 

Recently there has been a spate of new beltless “short magnums” introduced to the American market. Since they are all very similar in use and design, I will dump them all into one potpourri. The .300 Remington Short Action Ultra Magnum (RSAUM), .300 Winchester Short Magnum (WSM), and .300 Ruger Compact Magnum (RCM), are all cut from the same cloth.

They are intended to be the answer for the hunter looking for more power in a short, light, rifle. I suppose they serve that purpose. I have owned and hunted with a .300 WSM and tested both the .300 RSAUM and .300 RCM. If there is any difference, I could not detect it.

They all kick and roar in the mini-guns for which they are chambered, and do nothing much that a .30-06 won’t do. If I want or need a .300 magnum, I will just step on up to a .300 Winchester Magnum or .300 Weatherby. Otherwise I will stick with a .30-06 or a .308.

There is the line-up and what I think about them. Now you decide what you need.


Email Steve LaMascus at [email protected]


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