The CBJ MS or Modular System is a personal defense weapon, designed by Bertil Johanson, a Swedish arms designer, who established a CBJ Tech AB private arms manufacturing company. This PDW was revealed in the early 2000s. This compact weapon is intended for non-frontline troops, commanders, vehicle drivers, tank and artillery crews, pilots, medical teams and other support personnel. Currently this weapon system is in a final stage of development, however it received no production orders to date. The CBJ MS is based on the Izraeli Uzi submachine gun.
It is a blowback operated, selective fire weapon. However a replacement bolt group can be installed and the gun will fire from a closed action It is chambered for a newly-developed 6.5 x 25 mm high- velocity ammunition. It is claimed that performance of this round exceeds the standard ball 5.56 mm NATO ammunition. It is also claimed that in some cases it outperforms even the standard NATO 7.62 mm ball rounds.