6mm BR

The 6mm BR is a centerfire cartridge created for benchrest shooting. The cartridge is also known as the 6mm Bench Rest or simply 6 BR, and has also developed a following among varmint hunters because of its efficiency.^[2] There are two basic variants of very similar dimensions, known as the 6mm BR Remington and the 6mm Norma BR.

Cartridge history

Soon after the introduction of the .308×1.5" Barnes cartridge, wildcatters and experimenters began developing their own wildcats based on the cartridge. By 1963 there were several .22 (5.7 mm) and .24 (6.1 mm) caliber cartridges based on the Barnes’ cartridge. The new cartridges’ accuracy and efficiency was noticed by the bench rest shooting community. The .24 caliber (6.1 mm) cartridge version became known as the 6mm Bench Rest or the 6mm BR due to its widespread use in the sport of bench rest shooting.

Because the cartridge was a wildcat and was not standardized until several years later, several variations of the cartridge existed. Cases required fire forming in the chamber as chambers of the rifles varied from one to another.^[3] Several 6mm BR variants exist apart from the Remington and Norma versions: the 6mm BRX,^[4] 6mm Dasher,^[5] 6 mm BRBS^[6] 6 mm UBL.^[7]

In 1978 Remington started manufacturing their Remington 40-X rifle in the 6mm BR and named their version of the cartridge the 6mm Bench Rest Remington.^[8] By 1988 Remington was also manufacturing ammunition.^[9] Remington continues to offer the 6mm BR Remington in the 40-X series rifles.^[10] The Remington version of this cartridge is now considered to be obsolete.^[9]

In 1996 Norma of Sweden introduced the 6mm Norma BR which was dimensionally similar to the 6mm BR Remington. However the chamber of the Norma version provided a longer throat making allowances for the seating of VLD bullets.^[9] This is the most common variation of the cartridge used today.^[11]

The 6mm Norma BR has become a popular chambering in match rifles used in 300 metres (328 yd) ISSF and CISM and other 300 metres rifle disciplines.^[12][13]

Design

The 6mm BR Remington cartridge is based a necked down .308×1.5" Barnes cartridge which in turn is based on the .308 Winchester case shortened to 1.5 inches (38 mm). It is one of the earlier cartridges to follow the short, fat design concept. Short fat cartridges have characteristics that make them more efficient and accurate.^[14]

6mm Norma BR

The 6mm Norma BR cartridge was introduced by Norma in 1996. It is based on the 6mm BR Remington cartridge, although where Remington's cartridge was intended for bullets of about 70 grains (4.5 g), Norma standardized their set of chambering specifications for a very low drag (VLD) bullet of over 100 grains (6.5 g), thus realizing the long-range capabilities of the cartridge. This required a much longer throat in rifles chambered for the Norma cartridge.^[15]

See also

• List of rifle cartridges
• 6 mm caliber

References

External links

• 6mmBR.com - 6mm BR Rifle Shooting and Reloading Information
• 6mm BR Remington page at ChuckHawks.com

Cartridges derived from the .250-3000 Savage or its derivatives (including wildcats)
First generation	.22-250 Remington 6 mm XC .250 Ackley Improved .300 Savage
Second generation	Based on .300 Savage .308 Winchester Based on .22-250 Remington .22-250 Ackley Improved
Third generation	Based on .308 Winchester .243 Winchester .260 Remington 7mm-08 Remington .307 Winchester .308×1.5-inch Barnes 7.62×51mm NATO .338 Federal .358 Winchester
Fourth generation	Based on .243 Winchester .243 Ackley Improved Based on .307 Winchester .356 Winchester Based on .308×1.5-inch Barnes .22 BR Remington 6mm BR 7mm BR Remington .30 BR

Remington Firearms and Cartridges
Rifles	Bolt-action JuniorTarget 521TL Remington-Keene rifle M1903 Springfield rifle Pattern 1914 Enfield M1917 Enfield Model 5 Model 6 Model 7 Model 30 Model 34 M40 Model 341 Model 504 Model 511 Model 512 Model 513 Model 521 Model 580 Model 581 Model 582 Model 600 Model 660 Model 673 Model 700 Model 710 Model 720 Model 721 Model 722 Model 725 Model 770 Model 788 Model 798 Model 799 M24 Sniper Weapon System M2010 Enhanced Sniper Rifle Modular Sniper Rifle Pump-action Model Six Model 14 Model 121 Model 141 Model 572 Model 572 Fieldmaster Model 760 Model 7600 Model 7615 Semi-automatic Nylon 66 Model Four Model 8 Model 24 Model 241 Model 522 Model 552 Model 597 Model 740 Model 742 Model 7400 Model 750 R5 Remington Gas System Model R-15 Model R-25 RSASS Automatic Adaptive Combat Rifle Single shot Rolling Block
Shotguns	Pump-action Model 10 and 29 Model 17 Model 31 Model 870 Model 887 Semi-automatic Model 11 Model 11-48 Model 58 Model 878 Model 1100 Model 11-87 Model SP-10 SPR 453 Break-action SPR 100 SPR 310
Handguns	Semi-automatic 1911 R1 Model 51 R51 RM380 RP9 Remington RP45 Revolver Model 1858 Model 1875 Model 1890 Derringer Model 95 Rider Single Shot Pistol Zig-Zag Derringer Other XP-100
Cartridges	.17 Remington Fireball .17 Remington 5mm Remington Magnum Rimfire .22 BR .22 Remington Jet .221 Remington Fireball .222 Remington .222 Remington Magnum .223 Remington .22-250 Remington 6mm BR 6mm Remington .25 Remington .257 Roberts .25-06 Remington .260 Remington 6.5mm Remington Magnum 7mm BR Remington 7mm-08 Remington .280 Remington 7mm Remington Magnum 7mm Remington Short Action Ultra Magnum .30 Remington .30 Remington AR .300 Remington Short Action Ultra Magnum .300 Remington Ultra Magnum .32 Remington 8mm Remington Magnum .338 Remington Ultra Magnum 7 mm Remington Ultra Magnum .35 Remington .35 Whelen .350 Remington Magnum .375 Remington Ultra Magnum .416 Remington Magnum .44 Remington Magnum