The 22 BR Remington is based on the 308 x 1-1/2 inch Barnes case necked down to 22 caliber and lengthened by 0.020 inch with the shoulder angle increased to 30 degrees. Remington standardized the dimensions in 1978 as their 22 BR. It is one of the series of BR cartridges including the 6mm and 7mm, all based on the same case. The 22 BR has won many honors in benchrest competition and has great accuracy potential. The 22 BR is similar to the 22 PPC but has a case of larger base diameter and slightly greater powder capacity with the same case length. There isn't anything one can do that the other can't duplicate. Both can push a 55 grain bullet at over 3000 feet per second and duplicate the performance of the 223 Remington. Both are extremely accurate and make excellent varmint cartridges as well as benchrest competitors. 

This text is based on information from “Cartridges of the World”, Hodgdon reloading manual, the cartridge designer and/or own resources.