Rifling is ?

Ans. is 'c' i.e., Spiral groove inside nozzle Rifled arms The bore of the rifled weapon is scored internally with a number of shallow spiral grooves varying from 2 to more than 20, the most common being 6. These grooves run parallel to each other but are twisted spirally from the breech to muzzle. These grooves are called rifling and the projecting ridges between these grooves are called lands. Examples of rifled firearms are Pistals, rifles and revolvers.