.300 Rem. SA Ultra Mag. Load Data & Reloading Guide

The .300 Remington Short Action Ultra Magnum, commonly known as the .300 RSAUM, was introduced by Remington Arms in 2001. It was developed as part of a trend in the early 2000s towards creating short-action magnum cartridges. This innovation aimed to provide the powerful performance associated with longer magnum cartridges but in a compact form that would fit standard short-action rifles. The design capitalizes on the beltless case, which improves case head strength and facilitates smoother feeding and extraction in semi-automatic and bolt-action rifles.

The .300 RSAUM is based on the .404 Jeffery case and is necked down to accept .30 caliber bullets. It features a case length of approximately 2.015 inches and an overall length of 2.825 inches, allowing for high powder capacity in a short action configuration. This configuration provides excellent ballistics and efficient powder burn. Typical bullet weights range from 150 to 200 grains, offering a versatile spectrum for various applications. With muzzle velocities typically ranging from 2900 to 3300 feet per second, the .300 RSAUM delivers impressive downrange energy, suitable for both medium and large game.

Ammunition reloaders appreciate the .300 RSAUM for its strong performance and adaptability. The beltless case design aids in consistent chambering and extraction, reducing potential issues in handloading setups. The relatively short case allows for efficient powder burn, making it easier to develop loads that maximize velocity without exceeding pressure limits. This caters to reloaders looking for tailored performance in hunting or competitive scenarios. Moreover, the strong case head design ensures long case life, optimizing the reloading process and extending the usability of each case.

In practical applications, the .300 RSAUM is favored by hunters pursuing elk, deer, and even bear, given its capacity to deliver substantial energy at various ranges. Additionally, its design offers a smooth shooting experience with manageable recoil compared to some of its long-action magnum counterparts, making it an attractive option for competitive shooters who demand consistent accuracy and reliable performance from a compact platform. Overall, the .300 Remington SA Ultra Mag represents a well-balanced choice for those seeking power without compromising on rifle size and portability.