.224 ICL Marmot (P.O. Ackley Data) |
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| Warning! Notes: Standard twist: 14". The ICL Marmot is an Improved Swift, but unlike some other versions, factory loads cannot be fired in the ICL chamber. Doubtless this is a good idea, because the standard Swift is certainly maximum capacity for a .224, and when blown out, without shortening, it becomes quite badly over bore capacity. By shortening the case in order to keep the capacity to a better level, a good efficient cartridge is the result, possessing the advantages of an "improved" design, without getting over bore capacity, which always happens when the original length Swift case is blown out. (Handbook for Shooters & Reloaders/Vol. 1 - P.O. Ackley, 1962) NOTE: USE THIS DATA WITH EXTREME CAUTION |
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Cartridge History
.224 Caliber Cartridges The .224-caliber class of cartridges represents one of the most diverse and innovative segments in modern small-bore rifle development. Spanning both factory offerings and a wide range of wildcat designs, .224 cartridges have long been favored by varmint hunters, target shooters, and experimenters for their combination of high velocity, flat trajectory, and inherently low recoil. From early experimental rounds developed during the mid-20th century to modern high-performance designs, the .224 bore diameter has served as a platform for continual refinement in efficiency and ballistic performance. One of the defining characteristics of .224 cartridges is their adaptability. Case designs range from small, efficient cases optimized for moderate velocities and long barrel life to larger, high-capacity cases intended to maximize speed and downrange energy. Wildcat cartridges such as the various Ackley-inspired designs, benchrest variants, and proprietary experimental rounds illustrate the ongoing effort among handloaders to fine-tune performance through case geometry, shoulder angle adjustments, and improved powder efficiency. Factory cartridges within the .224 family similarly reflect decades of development aimed at improving accuracy, reliability, and overall ballistic consistency. Typical bullet weights for .224-caliber cartridges generally fall between 35 and 80 grains, allowing shooters to tailor loads to specific applications. Lighter bullets are commonly used for varmint and predator hunting where high velocity and rapid expansion are desirable, while heavier projectiles provide improved wind resistance and stability for longer-range shooting. The wide availability of component bullets and powders makes the .224 bore particularly attractive to handloaders seeking precise control over velocity, pressure, and accuracy. Handloading practices for .224 cartridges emphasize careful case preparation, consistent neck tension, and precise powder measurement to achieve optimal results. Because many .224 designs operate at relatively high velocities, attention to seating depth and incremental load development is especially important to maintain both safety and accuracy. When properly developed, loads in this caliber range are capable of exceptional precision, often delivering sub-minute-of-angle performance in well-tuned rifles. Overall, the .224 caliber continues to hold a significant place in the evolution of small-bore rifle cartridges. Its balance of efficiency, accuracy, and versatility has ensured its longevity among both factory rifle platforms and experimental wildcat projects. Whether used for precision target work, field applications, or continued ballistic experimentation, .224-caliber cartridges remain a cornerstone of modern rifle shooting. Source: Wolfe Publishing |
| Be Alert: Publisher cannot be responsible for errors in published load data. |
| Wt. | Bullet | Powder Manufacturer | Powder | Charge | Velocity (FPS) | |
| 50 | IMR | IMR-4895 | Subscribe | 3875 | ||
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| 55 | IMR | IMR-4895 | Subscribe | 3755 | ||
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