The 6 BRX is another improved 6mmBR round. The 6 BRX starts with a 6mmBR case and moves the shoulder forward .100". The 6 BRX maintains the 30 degree shoulder and the overall case length of the original 6mmBR round. This 6 BRX is popular with competitors shooting 1000 yards with the 6mm bullet. This round has been hard for us to replicate. There is no SAAMI standard specification for this round. There is a big variance in the chamber reamers used for 6 BRX. Harbour Arms has come up with a compromise that seems to work in most chambers. If you receive a 6 BRX and it does not work properly, contact us and we will work with you on a Precision Snap Cap that will work in your chamber. Although there is only one in the picture, Two Precision Snap Caps per package.