Notes from the Lab: .350 Remington Magnum

The .350 Remington Magnum was introduced in 1964, with production first appearing in 1965 as the Remington Model 600 Magnum bolt with an 18-inch barrel. Around 1968 the 660 Magnum appeared with a 20-inch barrel. After the discontinuance of the 600/660 rifles in 1971, the .350 Magnum was chambered in the Model 700. Other companies have likewise chambered rifles, including Ruger with its Model 77.

The .350 Remington Magnum was a unique that was ahead of its time. It was based on the belted magnum case (or .375 H&H Magnum), but shortened with an overall cartridge length of 2.800 inches to allow it to function in .308 Winchester-length bolt-action rifles and featured a 25-degree shoulder. Case capacity (measured with water to the base of the neck) was more or less identical to the .30-06 (depending on case make). Standard bullet diameter was .358 inch, with advertised ballistics pushing a 200-grain bullet to 2,710 fps, or a 250-grain at 2,410 fps. Essentially this was a short, fat magnum before the current crop of modern short magnums that have achieved some popularity in the last decade or so. With proper bullets, it is suitable for all North American game and African plains game.

In a Classic test with 22-inch barrel, 200-grain Remington factory loads clocked 2,607 fps, or around 100 fps short of their advertised velocities. Using the 200-grain Hornady SP bullet, more or less duplicating or exceeding factory load performance was done with several powders including Hodgdon H-4198, H-4895; Accurate AAC-2520, IMR-4320 and Vihtavuori N- 140. Switching to 250-grain bullets, IMR-4320 and Alliant RL-15 powders reached over 2,400 fps, which effectively duplicates .35 Whelen factory load ballistics.

In spite of being based on the belted magnum case, standard non-magnum primers (Remington 9 ½) produced reliable ignition and gave the lowest extreme spreads. If a magnum primer is used, maximum charges must be reduced to compensate for the increased pressures.