.340 Weatherby Magnum (using Hornady bullets)
Date: Jun 19 2013
The .340 Weatherby Magnum was introduced in 1962 and is based on Roy Weatherby’s .300 Weatherby Magnum cartridge necked up to accept .338-inch bullets. Both cartridges are based on the belted .300 H&H Magnum case blown out to significantly increase powder capacity. The .340 is an outstanding large game cartridge ideal for moose, Alaskan brown bear and African plains game, and offers high velocity, a flat trajectory and enough muscle for long range work.
Weatherby cases were used to develop the accompanying data, which are high quality and handled maximum loads (up to 62,500 psi) with ease. Federal 215 Large Rifle Magnum primers were used, which were originally designed to reliably ignite the large powder charges associated with Weatherby cartridges.
Some labs report that reduced or "start" loads can produce erratic pressures, however, this was not experienced with any of the loads listed.
Several powders gave notable performance (accuracy and velocity) including Hodgdon H-4350, H-4831, IMR-7828, Vihtavuori N-165, Alliant Reloder 19 and Reloder 25. Incidentally, Reloder 25 easily duplicated and even exceed Weatherby factory load ballistics with 225- and 250-grain bullets.