The 6mm Norma Bench Rest (6mm Norma BR) was introduced in 1996, one of several variants of a short 6mm cartridge intended for supreme bench rest accuracy. 6mm Norma BR is based on the 308 case shortened to 1.5598 inches and necked down to take a .243-inch bullet, using a Small Rifle primer. The 6mm Norma BR is dimensionally similar to the 6mm Bench Rest Remington, but Norma's specifications call for a longer throat allowing "seating out" of longer bullets. With the efficiency of its short, fat case the 6mm Norma BR produces surprising velocity, with a 105-grain bullet at 3045 fps. 6mm Norma BR has become the most common of the several 6mm variations for bench rest competion.
