.280 Ackley Improved
Some people refer to it as the .280 Improved. Other people call it the .280 Ackley. On casings made by Peterson, they are headstamped .280 Ack Imp. Whichever way you refer to it, the concept popularized by gunsmith and wildcatter P.O. Ackley, is here to stay. Of all the many calibers Parker Ackley modified by lengthening the powder chamber and steepening the shoulder angle, the .280 Ackley is the only one, so far, that has been adopted by SAAMI. And it is a high performer.
According to Derek Peterson, president of Peterson Cartridge, “The .280 Ackley Improved casing will launch a 7mm, 120 gr. bullet over 3,400 fps. The .280 Ackley has a similar velocity to the 7mm Rem Mag, when using light to mid-weight bullets. It also tends to produce less recoil, and less muzzle blast. When comparing the 280 Ackley with similar size cartridges, it has heavier bullet options than the 270 Win, and a flatter trajectory than the .30-06 Springfield.”
Peterson continued, “The.280 Ack Imp casings made by Peterson are designed for reloading. Our .280 AIs have an ultrahard head, and a thicker web which allows them to tolerate high pressure. It also results in you getting more reloads per case.”
“Speaking to the 280 AI chamber design, the concept was that you could ream out the chamber of your .280 Rem rifle to the Ackley dimensions, which sharpened the shoulder angle to about 40 degrees. Then, after the first firing of your factory loaded .280 Rem ammunition, the casing would fire-form into the new shape. The newly formed case would then hold more powder, and send bullets faster and flatter on subsequent reloads.”
Peterson concluded, “Some people use the made-up term “Ackley-ized” to refer to Ackley’s concept of steeper shoulder angle and taller powder chamber. Sometimes, around our shop, we use the term “Peterson-ized” to refer to how our casings have increased hardness values and improved web design to hold more pressure and get more reloads. To take advantage of both concepts, give the new .280 Ackley Improved casings from Peterson Cartridge a try.”
Warning: Only use Peterson Cartridge Co. casings in firearms in good condition, designed, marked, and chambered for this cartridge. Do not use Peterson Cartridge Co casings for “fire forming” or any other purpose other than what they were designed and tested for. Peterson retains no responsibility for the enclosed casings if they are used outside of the manufacturer’s recommendations.