Rifle cartridges come in every shape, size, variation, and application imaginable. Since the 8mm Lebel released in 1886, designers and wildcatters have been trying to build a better mousetrap. As technology develops, different trends appeared to compensate for the limitations of the day. Cartridge design can be broken up into different eras and this article will provide a large scale picture of the evolution of smokeless cartridge design.
Rimless Cases
The first leap forward after the development of smokeless powder was the design of rimless cases. Initially, the earliest smokeless powder cartridges looked a lot like the black powder cartridges that preceded them. Designed to work in the popular revolver, breach loading, and lever action designs, rimmed cartridges were the norm. With the development of modern military rifles using box magazines, rimlock became a common issue.
Rimlock occurs when the rim of the cartridge at the top of the magazine becomes hooked on the rim of the cartridge below it. This locks up the action. As militaries looked to solve this issue a number of rimless cartridge designs became standard military issue around the world. Some classic cartridge examples from this era are the 7mm Mauser, 6.5 Swede, and the 30-06. This family of cartridges continued to expand as these cartridges were necked up and down. Notable derivatives from this era are the 270 Winchester, the 257 Roberts, and the 8mm Mauser.
These new rimless cartridges fed smoothly from detachable box magazines, and the new bolt action designs provided the accuracy needed to take advantage of the increased reach provided by smokeless powder. These new cartridges allowed the shooter to extend their effective range from 150 yards to 300 yards, where iron sights become difficult to use in the field.
The Magnum Craze
From the early 1900’s to the 1950’s, cartridge development proceeded along at a modest pace. This all changed in the 1950’s. Riflescopes hit the point where they were reliable and affordable enough for the average hunter. This meant that for the first time hunters could see game further than they could shoot with iron sights. Visibility was no longer the limiting factor on the average shooters effective range.
However, long shots on game were still a challenge due to bullet drop. Hunters could now see their quarry, but they didn’t know how high to aim to hit it. They needed a way to flatten their trajectories to account for mistakes in range estimation. The solution: Velocity.
The 1950’s and 1960’s saw a host of fire-breathing magnums with screaming velocities and flat trajectories. New slower burning powders allowed larger cartridges to take advantage of their extra case capacity. Cartridges like the 338 Winchester Magnum, 264 Winchester Magnum, 300 Winchester Magnum, and the 7mm Remington Magnum all owe their creation to this trend. The Weatherby family of cartridges is iconic for this era. Cartridges like the 7mm Remington Magnum, 257 Weatherby Magnum, and 264 Winchester Magnum allowed hunters to stretch their maximum point blank range out to 350 yards or more.
Bigger is Better
However, Magnum Mania didn’t stop in the 60’s. With the technology of the time, velocity was the only way to increase effective range. Cartridges kept getting bigger and bigger. This trend culminated in the 1990’s the Remington Ultra Magnum and Lazzeroni families of cartridges. These hotrods are comically overbore, burning barrels in hundreds, not thousands of rounds and spitting bullets out at eye-watering speeds.
At the same time, rifle manufacturers were looking at how to maintain velocity in lighter weight packages. The short magnum boom was about to begin. Winchester created their Winchester Short Magnum (WSM) family and Remington responded with their Short Action Ultra Magnum (SAUM) family of cartridges. While few of these cartridges have survived to the modern day, the 300 WSM is still popular and the 7 SAUM enjoys a small cult following.
The Advent of the Laser Rangefinder
In the late 2000’s the magnum era finally came to an end with the advent of the laser rangefinder. In perhaps the biggest leap in the evolution of smokeless cartridge design to date, shooters could now know how far away their target actually was. Range estimation was no longer the limiting factor in how far one could shoot. Instead, wind became the dominant constraint.
Ammunition companies quickly realized that bullet efficiency has a much greater effect on wind drift than velocity. New, high-BC bullets were developed that could buck the wind and stay on target at long range. Unfortunately, existing cartridges often didn’t have the twist rate, or magazine space to utilize these new cutting edge bullets.
Over the last 20 years, we have seen a deluge of new cartridges designed to tackle this problem. The Creedmoors, PRCs, and improved BRs all follow a similar recipe. They increase head height and twist rate, giving space for the new long sleek bullets. Additionally, they tighten up the throat geometry as modern manufacturing has improved quality control such that loose tolerances are no longer necessary to guarantee reliability. Finally, they drop velocities to more moderate ranges, where recoil is less, barrel life is better, and accuracy is more forgiving.
Candidly, some of these new cartridges have yet to stand up to the test of time. However, if I were a betting man, the 6.5 Creedmoor, 6.5 PRC, 7 PRC, and 6 Creedmoor will be just as popular as the 30-06 Springfield and 300 Winchester Magnum are today.
Closing Thoughts
In closing, I don’t harbor any ill will towards the classic cartridges, and I appreciate their place in solving the problems of the day. If you want to shoot a classic cartridge, they still kill game just as reliably as they did upon their release. Looking forward, we may be on the cusp of a new era of high pressure cartridges, providing full size performance in compact platforms. On the other hand, this trend may prove to be a fad. Either way, the evolution of smokeless cartridge design has always been about solving the problems of the day, and that is no less true now than it was in 1886.