November 04, 2020
When P.O. Ackley gave the .280 Remington a steep 40-degree shoulder and straightened out most of the cartridge case’s body taper, he likely knew he was on to something special. However, it’s doubtful he anticipated that more than a half-century later, his .280 Ackley Improved cartridge would blossom into a favorite of savvy open-country hunters across the West.
Decades ahead of his time in cartridge design, Ackley became a household name for his work, at least among cartridge enthusiasts. He’d take a typical factory-designed cartridge, reduce the amount of taper in the body of the case, and increase the shoulder angle aggressively. These modifications resulted in added capacity, which increased velocity, and less case stretch, which resulted in longer case life.
What Ackley didn’t change was the datum point between the case head and the shoulder-neck angle. In a pinch, standard .280 Rem. ammo can be used. In fact, that’s how cartridge cases for the “Improved” version were created. Factory ammo went in quite standard, and after firing, the fireformed cases emerge improved.
The .280 Ackley Improved (.280 AI) was registered with SAAMI in 2007 by Nosler. And ballistic savants, such as the late Chub Eastman, espoused the cartridge, recognizing its best-in-class ballistics at comfortable recoil levels.
Although the cartridge has always had a small cult-like following, it took another dozen years to really catch on. Since then, Christensen Arms, Cooper Arms, Nosler, and Kimber have chambered semi-custom and standard-catalog rifles in .280 AI. Nosler offered factory-loaded ammunition and reloading components. The cartridge still didn’t gain the popularity it deserved.
Then, in 2019, Hornady introduced a 162-grain ELD-X bullet loaded in the .280 AI, adding it to the excellent Precision Hunter line of ammunition. Factory data has it exiting the muzzle at 2,850 fps, just 90 fps slower than the same bullet in Hornady’s 7mm Remington Magnum ammo.
Nearly concurrently, Federal announced it was working on three different .280 AI loads, including a Berger bullet and Federal’s own Terminal Ascent and Trophy Copper bullets. Plus, Petersen Cartridge offered premium .280 AI cartridge cases. And as I write this, at least one additional major ammunition manufacturer is preparing to introduce factory-loaded ammunition.
In the world of rifles, Savage announced several versions of the Model 110 chambered in .280 AI. Bergara added the cartridge to its chambering options. Ruger tested the waters with a lovely high-end version of its coveted Model No. 1 chambered for the cartridge and a year later announced the .280 AI in the superb Hawkeye African line of rifles. Weatherby included the .280 AI in its shockingly lightweight, top-shelf Backcountry rifle line. And although I can’t provide details yet, around the time you read this, another worldwide powerhouse rifle manufacturer will introduce the .280 AI across the spectrum of its hunting rifles.
Finally, the .280 Ackley Improved is rocketing to western-hunting stardom.
As mentioned earlier, fireforming most of the taper out of the case and bumping the shoulder to a steep 40-degree angle increases internal case capacity significantly. In my experience, the .280 AI generates nearly as much velocity as the popular 7mm Rem. Mag. and uses 10 to 15 percent less powder to do so. As a result, recoil is around 5 percent less. Remember, ejecta (exploding gases and particulates exiting the muzzle) contributes greatly to recoil. Therefore, less ejecta equals less kick.
On the subject of efficiency, .280 AI cases don’t stretch much each time they’re fired. Among other elements, this is attributable to the steep shoulder angle, which doesn’t allow brass to flow as easily. Good brass, once obtained, lasts a long time.
Importantly, although SAAMI spec’d the .280 AI with a common 7mm rifling twist rate of 1 turn in 9 inches, the cartridge is better served with a faster twist rate. Ideally, something in the 1:8 range. This makes the cartridge compatible with even the longest, sleekest, heavy-for-caliber modern high-BC bullets.
Such projectiles drop less and drift less in the wind, even though they do start out a bit slower than light-for-caliber bullets. If you have a rifling twist that’s fast enough, the .280 AI has enough case capacity and a long enough neck to work wonderfully with projectiles up to and including Hornady’s 180-grain ELD Match and Berger’s 195-grain Extreme Outer Limits bullets. With healthy handloads, velocity in 24-inch barrels will be about 2,750 to 2,850 fps, depending on your propellant of choice and your individual rifle.
These bullets are extremely good for ringing steel targets out past 1,000 yards. However, for hunting, there are better balanced options for the .280 AI. At the top end, for extended-range work, I like Hornady’s 175-grain ELD-X. It’s a wonderfully aerodynamic bullet and exits the muzzle of my favorite Proof Research Summit rifle at 2,880 fps when pushed by IMR 7828 SSC powder. Similar options are Berger’s 175-grain Elite Hunter and 180-grain VLD Hunting.
I’ve also had superb results with Berger’s 168-grain VLD Hunting. It’s a legitimate, repeatable 0.40-MOA bullet in my Proof rifle, and even though velocity with that tuned handload is modest, at 2,870 fps, it has proven to be excellent on mule deer and elk. Oddly, I think the modest velocity is one reason that particular bullet performs so well in the .280 AI—it’s not going quite fast enough to grenade on impact up close.
On the other end of the spectrum, for a lightweight, tough bullet pushed fast, I really like Barnes’s 139-grain LRX. Handloaded to a sizzling 3,200 fps, it’s flat and forgiving for shots inside a quarter-mile. I zero it at 300 yards, and it drops just 8 inches at 400 yards. Muzzle energy is about 3,400 ft-lbs. A technician friend at Barnes used this bullet right after it was introduced for a once-in-a-lifetime free-range bison hunt in Utah and shot a large, old bull right at 600 yards with his .280 AI rifle. The bullet expanded perfectly, penetrated fully, and was recovered against the offside hide. It was intact and weighed nearly 100 percent. I’ve watched my hunting partner Thomas Provstgaard shoot the 139-grain LRX clean through stout-bodied African plains game, including a steeply angled shot on a massive 55-inch kudu bull. It’s a tremendous bullet.
My original .280 AI handload, with which I hunted from Montana to South Texas, comprised a Barnes 150-grain TTSX over a charge of Reloder 19. Muzzle velocity was 3,060 fps, right there with advertised 7mm Rem. Mag. speeds with the same bullet. Energy up front was over 3,100 ft-lbs. It was a sub-0.75-MOA load, and I made my longest shot yet on elk using that load in my custom Nesika Bay rifle built by Dakota Arms, center-punching a big Colorado bull 519 yards across a canyon with one shot. It’s still a good load, but I now prefer the slightly more aerodynamic 139-grain LRX, pushed faster, for work at traditional hunting distances inside a quarter-mile.
Last, but not least, I’ve come to love Federal’s 155-grain Terminal Ascent bullet. Factory .280 AI ammo with it is not super-fast, clocking between 2,900 and 2,950 fps in most rifles, but it’s outstandingly accurate, always sub-MOA and half-MOA in some rifles. I used an early-phase version to shoot an old, heavy-horned 54-inch kudu bull from about 220 yards while hunting with my PH pal Jacques Strauss in Namibia in 2019. Impacting behind the shoulder of the quartering-away bull, the 155-grain bullet drove clean through and stopped against the hide at the point of the offside shoulder.
Just for reference, the .280 AI will shoot a light 140-grain bullet about 300 fps faster than the .270 Winchester can. And loaded judiciously, it will push heavy VLD-type 180-grain bullets as fast as the 7mm Remington Short Action Ultra Mag.
While on the subject of velocity, allow me to point out that the .280 AI really deserves a 24-inch barrel. Going longer gains little; going shorter loses too much.
Let’s pause and take a look at why the 7mm/.284 bore diameter is significant.
Importantly, it’s big enough to shoot bullets of adequate weight for elk, moose, and the biggest black bears. There’s a reason that over 50 years ago, the 7mm Rem. Mag. put the .264 Winchester Magnum out of business in short order. That reason was heavier bullets. A .284 bore comfortably pushes bullets of 140 to 180 grains. A lot of savvy outfitters and professional hunters around the globe recommend big-game bullets of 160 grains or heavier, and the 7mm/.284 bore diameter meets that handily without greatly exceeding it. Excellent capability without fanfare is the result.
On a related note, 7mm bullets offer a bigger, more effective frontal diameter than smaller 6.5mm and 0.277 bullets. As the mathematicians among us know, when you increase diameter, frontal surface area increases exponentially. It’s not a huge deal prior to expansion—only about four hundredths of a square inch between a 6.5mm/.264 and a 7mm/.284 diameter projectile. However, it is much more significant when the two expand. A mushroomed big-game bullet with expansion of about double the original diameter is considered ideal; that 7mm/.284-diameter bullet measures 0.568 inch across, with a surface area of over 1.01 square inches. Compare that to the 6.5mm/.264, which measures 0.528 inch across and has a surface area of 0.87. The difference is about 14 percent. It’s enough to significantly increase energy transfer, without impeding penetrating ability.
Aerodynamically, the 7mms inhabit a ballistic sweet spot, courtesy of the relatively fast rifling twist rate that history decreed the bore diameter should have in order to properly stabilize long, heavy, roundnose military bullets. Modern long-range 7mm projectiles typically have really high BCs—so high, in fact, that manufacturers have to get extreme in the 6.5mm and .30-caliber bullet lines just to come close.
For a decade or more, the .280 AI has been my favorite all-around cartridge for big game in the West. It has more puissance than the 6.5 Creedmoor or .270 Win., and in practical terms, it matches the 7mm Rem. Mag. with less recoil, more magazine capacity, and longer barrel life.
Up close, it wallops just like the .30-06, having similar bullet weight at similar velocities. However, way out there, it absolutely trounces the .30-06, thanks to the far better aerodynamics of the 7mm bullets.
When you bump up to the magnum .30s, comparisons change. With 200-grain bullets pushed at 2,900 fps or so, the big .30s clearly impact with more visible result—on both ends. Recoil is significantly greater. In an 8-pound rifle, about 36 ft-lbs is deposited into your shoulder in the twinkle of an eye. Compare that to a 175-grain 7mm bullet fired at 2,850 fps from the .280 AI, which generates less than 26 ft-lbs.
Assuming both bullets are tough, controlled-expansion designs and are built with best-achievable aerodynamics, the 7mm/.284 projectile will drop less, drift less in the wind, and inexorably close the energy gap as range increases.
A primary advantage of the .280 Ackley Improved is the increased magazine capacity. Being a standard .30-06-diameter cartridge case, nearly all popular bolt-action hunting rifles will hold at least four rounds in the magazine, and many models comfortably swallow five down, plus one in the chamber. Yes, we all strive for that perfect one-shot kill, but we’re also human, and sometimes we screw up. Having plenty of follow-up ammo on tap is a very good thing.
Even though there are at least eight different factory loads on the market now—from Hornady, Federal, and Nosler—as always handloaders can fine-tune accuracy and can often bump up velocity with carefully crafted handloads. Conveniently, the .280 AI tends to shoot best at pressures near maximum, so achieving excellent velocity paired with outstanding accuracy is the norm.
My favorite dies are by Redding, from its Premium line. Nosler brass has always been my go-to, because it’s invariably near-perfect and comes weight-sorted and prepped for accuracy, meaning trimmed to length, chamfered, and deburred, and with flash holes uniformed. Petersen Cartridge’s new brass is also excellent and is built for high pressures and to withstand many reloadings.
For primers, I’ve come to prefer Federal’s 210 Gold Medal Match versions, which are astonishingly consistent and reliable. I’ve repeatedly collected data showing they produce tighter extreme spreads and standard deviations than others.
Several propellants work wonderfully in the .280 AI. Choose medium-slow burn rate powders, such as H4831SC and Reloder 19 for light- to midweight projectiles. For the heavier bullets from 160 to 180 grains, H4831SC, Reloder 23, H1000, and IMR 7828 SSC are excellent.
There’s never been a better time to get into the .280 Ackley Improved game, and there’s never been a time when the cartridge has been more relevant. Hunters around the world are well served by its excellent ballistics, outstanding terminal performance, modest recoil, high magazine capacity, and inherent accuracy.
280 Ackley Improved Cartridge Accuracy & Velocity