aftershaft
/ˈæftsʃæft/Definitions
1. noun
A part of a firearm, especially a shotgun, consisting of a metal tube or shaft extending from the breech to the muzzle.
“The shotgun’s aftershaft was damaged in the accident.”
2. noun
A rearward extension of the drive shaft in a vehicle, typically containing the universal joints.
“The car’s aftershaft needed to be replaced due to excessive wear.”