6mm BR Norma

The 6mm BR Norma is the standardised, factory-loaded form of a benchrest wildcat. Soon after the .308 Winchester was cut down into the .308×1.5” Barnes, experimenters necked that short case to take .22 and 6mm bullets, and by 1963 the 6mm version was widely enough used in benchrest competition to be known as the 6mm BR. Remington chambered its 40-X rifle for its own version in 1978, and Norma of Sweden introduced this dimensionally similar version in 1996.

What separates the Norma round from the Remington one is the chamber rather than the case: Norma’s standard gives a longer throat, making room to seat very-low-drag bullets. The short, wide case was designed to balance accuracy, barrel life and case capacity for target shooting, and it has become a common chambering for 300-metre match rifles in ISSF and CISM competition. Several related wildcats grew out of the same case, and C.I.P. lists four variants of the family, of which this is the most widely used.

The dimensions and pressure ceiling on this page come from the C.I.P. datasheet for “6 mm BR Norma”. The Norma load carries a velocity the maker states for a 660 mm barrel; the two Lapua loads record bullet mass and ballistic coefficients only, because Lapua’s product pages give a muzzle velocity without naming the barrel it was measured in.