.338 Winchester Magnum (using Hornady bullets)
Date: Oct 08 2014
Winchester announced the .264 and .338 Winchester Magnums in 1958, which were "short magnums" for their era as they were designed to function in .30-06 length actions rather than the longer .300 and .375 H&H Magnum lengths. The .338 Winchester Magnum filled the gap between the .30-caliber magnums and the .375, and has proven itself versatile on large game. It is widely popular in Alaska among hunters and guides in pursuit of brow bear and moose, and is also popular in Africa for larger plains game. It offers a unique blend of flat trajectory and medium bore performance with comparatively manageable recoil.
In developing handload data the .338 Winchester Magnum delivered outstanding shot-to-shot consistency and accuracy without erratic pressure curves. In spite of many new .338-caliber cartridge developments in the decades since its introduction, the Winchester remains the most popular of all among hunters around the world.
If ammunition is to be used in multiple rifles, cases should be full-length sized to assure that they will chamber easily in all guns. If loading for a single rifle, to increase case life it is suggested to size cases so that they headspace on the shoulder rather than the belt.
When loading the Hornady 200-grain SR-RP bullet and seating it to an overall cartridge length of 3.340 inches, the cannelure will be approximately (depending on case length) .100 inch above the case mouth.
When using the Hornady 185-grain GMX bullet, several powders gave outstanding performance including Hodgdon H-4350, Norma N-204, Alliant FL-17, Western Powders Big Game and IMR-4350. With Hornady 225- and 250-grain bullets, notable powders included Hodgdon H-4350, H-4831; Vihtavuori VV-N160 and Alliant RL-19.
To achieve reliable ignition with all powders and in a variety of temperatures, large rifle magnum primers are suggested.