6.5 Rem. SA Ultra Mag. Load Data

Caliber Overview

The 6.5 RSAUM is a high-performance rifle cartridge based on the Remington Short Action Ultra Magnum case, necked down to accept 6.5mm (.264 caliber) bullets. It was developed by wildcatters seeking to maximize the long-range efficiency of modern 6.5mm projectiles while utilizing the inherently strong and compact SAUM case architecture. Although never standardized by SAAMI, the 6.5 RSAUM has become a respected choice among precision shooters, competitive long-range marksmen, and hunters seeking magnum-level performance in a short-action platform.

One of the cartridge’s primary advantages is its exceptional ballistic efficiency. The SAUM case provides a balanced powder capacity that allows shooters to push high-BC bullets such as the 140–156 grain class at impressive velocities, typically in the 2950–3100 fps range depending on barrel length and load. This gives the 6.5 RSAUM a notably flat trajectory and excellent wind resistance, outperforming more commonly known 6.5mm options like the 6.5 Creedmoor and 6.5 PRC when loaded to its full potential.

The RSAUM case is known for consistent ignition and uniform pressure curves, contributing to excellent accuracy when properly tuned. Its stout case walls and efficient geometry help prolong barrel life relative to other overbore magnums, though barrel wear is still higher than in mid-capacity cartridges. The 6.5 RSAUM’s recoil is generally moderate for its power level, making it manageable for precision applications where shot-to-shot consistency matters.

In hunting contexts, the 6.5 RSAUM offers ample energy for medium to large game, delivering deep penetration and reliable terminal performance at extended distances. While factory ammunition is limited, custom and handloaded options are widely supported in the long-range community.