.338 Ruger Compact Magnum (using Hornady bullets)
Date: Apr 07 2015
The .338 Ruger Compact Magnum was introduced in 2008 in a joint effort between Ruger and Hornady. The concept was a cartridge that could be housed in a .308 Winchester length action (although overall cartridge length is just slightly .030 inch longer) for reducing rifle weight and length. Furthermore, it offers medium bore performance on large game such as elk, moose, bears and African plains game. It utilizes powder efficiently, and in testing here produced low extreme spreads and was accurate. It is advertised to push a 185-grain GMX bullet at 2,980 fps a 200-grain SST at 2,950 fps or various 225-grain bullets at 2,750 fps. Trajectory of the Hornady factory loads is actually flatter at 500 yards than a 150-grain spitzer bullet fired from a .30-06 with a muzzle velocity of 2,910 fps. This performance makes the .338 RCM a versatile hunting cartridge under many field conditions.
The case is based on the beltless .375 Ruger case, but shortened and necked accordingly. It has similarities to the old Newton case, but is strong and modern in every respect. The shoulder is 30 degrees and water capacity is around 71.0 grains (filled level with the case mouth).
The only factory load available during testing contained the 225-grain SST bullet. The test rifle, a Ruger Model 77 Hawkeye stainless with a 22-inch barrel, averaged 2,669 fps for a five-shot string with this load.
The above velocities with 225-grain bullets were easily duplicated using Accurate 2520 powder. Other top performing powders included Vihtavuori N-540, N-550, Winchester 760, Hodgdon H-414, Norma 203B and Alliant RL-15.
With maximum powder charges that typically range between 50.0 and 60.0 grains, a standard (non-magnum) large rifle primer is suggested, which produced the lowest extreme spreads during tests. If a magnum primer is substituted, maximum charges must be reduced.