6.5-284 Norma
The 6.5-284 Norma originated as a wildcat cartridge based on the .284 Winchester cartridge necked down to 6.5 mm.

History 
The  parent case .284 Winchester was created around 1963, but did not see extensive commercial use.   The 6.5 caliber allowed for the use of long, aerodynamic bullets.  In 1999, Norma submitted it to CIP.  It has since been standardized as the 6.5mm-284 Norma.

Use 
The 6.5-284 has been used extensively in benchrest competitions and is known as an extremely accurate long range round. Using an improved version of the 6.5-284, Rich DeSimone set a  world record with a  group. Rich DeSimone's  record has been broken by Tom Sarver, who shot a  group in 2007 using a .300 Hulk wildcat cartridge that is based on the .338 Lapua Magnum cartridge. In contrast, most hunting rifles show similar accuracy at  to . A  bullet in this caliber is typically fired at  to .