45-70Govt is available commercially in plinker loads, much like 38S&W and 44-40Win. More impressively, almost a century and a half after its inception, a wide variety of hunting and precision 45-70Govt loads are also manufactured by companies large and small. As a result, historic artifacts like Springfield “trapdoor” rifles can be put to regular use even with new production low-pressure smokeless cartridges. Modern production variations on lever, falling block and bolt actions are still being introduced. This continued popularity stems from two factors, a minor technical one and a major political one.
The minor factor is the simplicity of safe reloading of this cartridge. Unlike most of the 1880s ammunition, it uses a straight wall case. Reloading it is as simple as working with a typical pistol cartridge, perhaps even simpler because of the sheer volume of the powder uses. 70 grains of black powder may be measured by weight or by volume, and making a small error is not critical. Loading with smokeless requires a little more attention to detail, and only the relatively mild original-power cartridges should be used in Springfield Trapdoor originals or reproductions, as well as the 19th century rolling blocks or lever actions. Modern Sharps and lever action reproductions, also 45–70 Gibbs Mauser conversions can stand stronger loads. Most modern lever actions and Ruger #1 falling block can hold up to even the maximum pressure supported by the case design: 300gr JHP at 2050fps or heavier bullets at a slightly lower velocity. Some commercial loads go beyond the original 500 grains, offering a very stable long-range bullet, though one that requires very careful range estimation.
But the technical factors alone cannot account for the retained popularity, especially since it has no effect on the factory production. And yet 45–70 remains available in far greater variety and at a fraction of the price of its once competitors. The main reason for this popularity is political: Americans have traditionally owned real guns. Not just small-bore shotguns made from surplus Russian Berdans or French Tabatière army rifles, but proper, long-range rifles equally suited for stopping a grizzly, anchoring a buffalo or putting daylight through the hearts and minds of hostile humans at a standoff distance. Unlike governments of most other countries, Switzerland being a conspicuous but small-scale exception for most of its history, the United States government sold off much of the army inventory to afford the newer and better gear. As that practice declined after 1968, taxes went up instead to buy more military gear while destroying surplus and obsolescent guns. But Springfield “trapdoor” rifles were sold off to the public in large numbers, and the popularity of the caliber made it popular with civilian gun makers. This became a self-reinforcing cycle that continues today. The main brake on the popularity of this caliber is the modern copy-cats, the rimless 450 Marlin and the rebated rim 458SOCOM, both of which promise the performance envelope of the modern 45–70 without having to worry about customers chambering the full power ammunition in the more fragile antiques. 450 Marlin delivers on that promise, while 458SOCOM hangs with the mid-range loads at most. 44 Magnum, although impressive performer in its own right, falls short with half the bullet weight at the same velocity or 750fps slower with the same projectile.