The 6mm BR Remington
By Chuck Hawks
The 6mm Bench Rest Remington was introduced by that company in 1978, chambered in their 40X target rifle. At first it was strictly a cartridge for reloaders, and cases had to be formed from Remington's Universal Bench Rest Brass. But at some point Big Green began offering 6mm BR factory loaded ammunition. Remington and Norma currently offer brass for handloading.
The 6mm BR is based on a very short, fat, thoroughly modern case designed by Remington's Jim Stekl. The case is 1.56 inches long with a 30 degree shoulder and a standard .473" rim diameter. The latter is important, as it mates with standard bolt faces, unlike the 6mm PPC and most other bench rest cartridges. This makes it easier to build a custom bench rest rifle. As a factory standardized cartridge, the overall length of the 6mm BR cartridge has been set at 2.2 inches. Like most 6mm target cartridges it uses small rifle primers and standard .243 inch bullets.
The 6mm BR was designed specifically for use in bolt action single shot rifles. The cartridge is not well suited for use in repeating rifles due to its very short, sharp shouldered case, which makes for serious feeding problems. It is often impossible to get this cartridge to feed from the magazine of even a custom made and tuned rifle. It should be restricted to use in single shot rifles.Remington's factory load for the 6mm BR drove a 100 grain bullet at a MV of 2550 fps with 1444 ft. lbs. of ME. At 200 yards the figures were 2083 fps and 963 ft. lbs. The trajectory of that load looked like this: +2.5 inches at 100 yards, -0.6 inch at 200 yards, and -11.8 inches at 300 yards. I am not sure about the intended purpose of this load, which I believe has since been discontinued. It would have required a rifle barrel with a 1-10 inch twist to stabilize the 100 grain spitzer bullet.
Handloaders using 6mm BR rifles for bench rest competition can load 60-70 grain HPBT match bullets at MV's in the 3100-3200 fps range with great accuracy. Such loads are directly comparable to similar match loads for the 6mm PPC.
Reloading data for the 6mm BR cartridge can be found in the Hodgdon and Nosler Reloading Manuals. The following data for varmint bullets is taken from the Nosler Reloading Guide #5.
The 55 grain Nosler Ballistic Tip varmint bullet showed a MV of 3112 fps in front of 27.0 grains of RL7 powder and 3720 fps in front of 31.0 grains of RL7. RL7 was the most accurate powder tested with this bullet. With the 70 grain Ballistic Tip bullet 28.0 grains of H4895 powder gave a MV of 2919 fps, and 32.0 grains of the same powder gave a MV of 3321 fps. H4895 was the most accurate powder tested with this bullet. The Nosler trajectory tables show the following for a 70 grain bullet at 3300 fps: +1.2 inches at 100 yards, 0 at 200 yards, and -6.1 inches at 300 yards.
Note: An article about the 6mm PPC and 6mm BR Rem. can be found on the Rifle Cartridge Page.
Copyright 2005 by Chuck Hawks. All rights reserved.