Tapering (firearms)

In firearms,Tapering refers to components that narrow down, similar to that of a conical fashion hence the name taper.

Barrels
In barrels, this centralises mass to the operator. Not only to reduce weight from the muzzle but also to increase accuracy/acquisition and stabilise the balance handling of the weapon. Also the fact that chamber pressures are higher at the rear of the barrel.

Rifling


In rifling, a Tapered bore/Conical bore is where the caliber narrows off to increase velocity of the round.

Cartridges
In cartridges, this usually helps in chambering/unloading the weapon. This differs than shouldering/bottlenecking as this only refers to the case head of the cartridge that holds the projectile, whereas tapering usually refers to the angled sides of the cartridge.