By Chuck Hawks
The .45-70-405 Government was introduced in 1873, when it became the official U.S. military cartridge. It was initially chambered in the military Model 1973 Springfield (Trapdoor) single shot rifle. The old fashioned nomenclature stood for .45 caliber-70 grains of black powder-405 grain bullet weight. There was also a .45-70-500 variant, loaded with a 500 grain bullet. Soon, many superior hunting and target style single shot rifles were being chambered for the .45-70.
The .45-70 cartridge is built on a straight walled case with a moderate .0255" of body taper. It has a large, fairly thick rim .608" in diameter that is typical of rimmed black powder cases. The case length is 2.105" and the loaded cartridge must not be more than 2.55" long if it is to be used in repeating rifles.
The .30-40 Krag superceded the .45-70 in 1892 as official U.S. military cartridge. The Krag was the first cartridge designed for smokeless powder adopted by the U.S. Army. The 45-70 was very popular as a sporting rifle cartridge in the last quarter of the 19th century, and so it made the transition to smokeless powder. It retained enough popularity to survive in the age of high velocity smokeless powder sporting cartridges ushered in by the .30-30 Winchester.
Winchester chambered their powerful Model 1886 lever action rifle for the .45-70, giving the cartridge a home in a popular repeater, which carried it well into the 20th century. The late gun writer Elmer Keith, for one, wrote many kind words about the old .45-70 during his long career. He helped to keep it alive through the 1930's, 40's, and 50's. Many surplus Siamese Mauser bolt action rifles were rechambered for .45-70, and also helped keep the cartridge alive.
The modern resurgence of interest in single shot rifles was initially sparked by the introduction of the Ruger No. 1. The subsequent introductions of the Browning 1885 High Wall, and a number of Trap Door Springfield reproductions, helped fan the flames. All of these rifles were chambered for the .45-70, and helped put the old cartridge on the comeback trail.
In 1972 Marlin chambered their big bore version of the 336 lever action, called the 1895, for the .45-70. In the late 1990's, Winchester reintroduced the Model 1886 lever action in .45-70. The advent of powerful repeating rifles in .45-70 gave the cartridge a major shot in the arm. The .45-70 was alive and well.
In 1998 Remington reintroduced the single shot No. 1 Rolling Block rifle. A couple of modern double rifles are being chambered for .45-70. Even some single shot pistols and one enormous derringer (!) are chambered for the old cartridge. At the turn of the 21st century the old .45-70 is probably available in more new guns than it has been for about 85 years. The .45-70 has made a remarkable comeback.
The very wide variety of action types, age, and condition of rifles for the .45-70 cartridge has resulted in three pressure levels of loads. The lowest pressure loads are for 1873 Springfield rifles, reproductions thereof, and other rifles of similar strength. These loads are held to pressures around 25,000 cup, essentially similar to the original loads for which these rifles were designed. Modern factory loads are intended to be safe in these rifles. The traditional factory load is a 405 grain bullet (BC .214, SD .272) at a MV of 1330 fps, and a ME of 1590 ft. lbs. This is a very moderate load that kills well because of the penetration of its big, heavy bullet. It has been used on all North American game, but today should be restricted to animals of around 400 pounds or less.
Although it can be very accurate, the trajectory of this load is such that it should be zeroed at 100 yards. From a scoped rifle so sighted, the bullet should hit about 2.3" high at 50 yards, and 9.5" low at 150 yards. It is about a 125 yard deer cartridge at best.
In an attempt to improve the low pressure .45-70 load, the factories have been loading a 300 grain JHP bullet (BC .171, SD .204) at around 1,810 fps. At that velocity, according to Remington figures, the ME is 2182 ft. lbs. This makes the .45-70 a sort of super .30-30 deer rifle.
The trajectory of this load allows a scoped rifle to be sighted as follows: +3" at 82 yards, +2.7" at 100 yards, -3" at 162 yards, and -10.2" at 200 yards. This makes the 45-70 about a 162 yard rifle for use on deer size game.
According to the third edition of the Hornady Handbook of Cartridge Reloading 45.3 grains of IMR 3031 powder can drive a Hornady 300 grain JHP bullet to a MV of 1500 fps, and 52.0 grains of IMR 3031 can drive the same bullet to a MV of 1800 fps. This essentially duplicates the factory loads. These and all Hornady loads to follow used Winchester brass and Federal primers; velocities were measured in the 29.5" barrel of a Springfield 1873 rifle.
The trajectory of the 350 grain bullet is nearly identical to that of the new .450 Marlin cartridge. From a scoped Marlin rifle the 350 grain RN bullet at 1900 fps can be zeroed as follows (Hornady figures): +2.4" at 50 yards, +3.2" at 100 yards, and 0 at 150 yards, and -8.0" at 200 yards.
The third category of hot .45-70 handloads is for modern single shot rifles like the Browning High Wall and Ruger No.1. These rifles can withstand the high pressures of modern high intensity cartridges, and .45-70 reloads for these can safely go up to 50,000 cup. There are some truly brutal loads for the old .45-70 in this category (at both ends of the rifle).
The Hornady 350 grain RN bullet can be driven to 2000 fps by 55.4 grains of IMR 3031 powder, and 2200 fps by 59.6 grains of IMR 3031. The Hornady 500 grain RN bullet can be driven to a MV of 1700 fps by 50.1 grains of IMR 3031, and 1800 fps by 53.1 grains of IMR 3031. There isn't much game anywhere in the world you could not take with such loads. They make the old .45-70 more powerful and versatile than the new .450 Marlin. And the single shot rifles can use spitzer bullets, which further flattens trajectory.
I have chronographed the Barnes-X 350 grain spitzer bullet (BC .402, SD .238) at over 2100 fps from the 28" barrel of my Browning High Wall. That load has a ME of 3427 ft. lbs. At 100 yards it is still traveling at 1909 fps, and has 2832 ft. lbs. of energy. At 200 yards its velocity is 1730 fps, and its energy 2326 ft. lbs.
Zero that load to hit 3" high at 100 yards, and it strikes about 2.2" low at 200 yards. Its maximum point blank range (+/- 3") is 207 yards. It has the killing power to lay 1000 pound animals low at 200 yards. The old time buffalo hunters never had anything like that!
Magnum Research also puts out a revolver in 45-70 as well.
I was wondering if IMR3031 wouldn't be a good propellant for the old warhorse. I found it about the best (though very slightly on the hot side) for 150 grain jacketed loads in a 30-06. I use about 50 grains there also.