How many existing basic design types are there of the weapons the United States and the Soviet Union had an arms race over?
Nuclear weapon design Nuclear weapon designs are physical, chemical, and engineering arrangements that cause the physics package of a nuclear weapon to detonate. There are three existing basic design types. In many existing designs, the explosive energy of deployed devices is derived primarily from nuclear fission, not fusion. (This includes fission of any U-238 tamper or casing due to fusion produced neutrons.)
23×152mm The 23×152mmB used by the USSR/CIS in the VYa-23 aircraft autocannon the Ilyushin Il-2 ground attack aircraft and in the 2A7 and 2A14 autocannons on the ZU-23 anti-aircraft gun series and ZSU-23-4 "Shilka", among others. Note that the ammunition for the VYa-23 uses a brass case and is not functionally interchangeable with the steel-cased ammunition of the modern ZU-23 anti-aircraft gun series. These two weapon systems use different headspace sizes, therefore requiring ammunition of slightly different dimensions.