.219 Zipper (P.O. Ackley Data)

.219 Zipper (P.O. Ackley Data)

The .219 Zipper, introduced by Winchester in 1937, is a rimmed wildcat cartridge based on the .30-30 Winchester case necked down to accept a .224-inch bullet. While it was originally created for lever-action rifles like the Winchester Model 64, P.O. Ackley later explored “Improved” versions of the Zipper—adjusting shoulder angle, case taper, and optimizing case geometry—to increase case capacity and improve velocity and performance in bolt or single-shot rifles.

Ackley’s data for the Zipper includes bullet weights ranging from ~45 to 55 grains. With modern handloads and carefully prepped brass, these weights can produce impressive velocities—often in the 3,000-3,400 fps range depending on barrel length and powder choice. Ackley emphasized that proper neck tension, case prep (especially consistent trimming and annealing), and good bullet seating depth are critical for achieving accuracy and avoiding pressure spikes, particularly in his “Improved” wildcat configurations.

According to the article "Modern Bullets From The .219 Zipper", which references parts of Ackley’s handbook, rifles used for testing included ones with 26-inch barrels and fairly fast twist rates. The data in there shows that with clean-burning medium powders, suitably designed bullets, and matched components, the Zipper can achieve surprising consistency—even keeping group sizes tight while getting good downrange performance.

Ackley’s approach often preferred bolts or single-shot rifles rather than lever actions for his improved versions, due to limitations of magazine type and feeding. The Zipper Improved wildcats are more suited to stronger actions that can handle higher pressures and free-float barrels for better precision. Although factory production never embraced Ackley’s full improvements, many custom loads made using his data show the practical gains in trajectory, energy retention, and bullet stability.

While commercial data and brass for the .219 Zipper are relatively scarce now, many of Ackley’s load suggestions remain valuable benchmarks for handloaders. His wildcat improvements still serve as reference points for shooters looking to build performance in older calibers—balancing speed, safety, and accuracy in rifles that were built for craftsmanship.

Source: Wolfe Publishing & P.O. Ackley Data