What is the purpose of the grooves in the rifled barrel?

The grooves in a rifled barrel are specifically designed to stabilize the bullet in flight. When a bullet is fired from a rifled barrel, the lands (raised portions) and grooves (depressed portions) impart a spin to the bullet as it travels down the barrel. This spin helps to stabilize the bullet by providing gyroscopic stability, similar to how a spinning top remains upright.

As a result, a bullet that is spinning properly will have a much straighter trajectory and better accuracy over distance compared to a bullet that is not stabilized. This is essential for effective shooting, especially at longer ranges, where accuracy can be significantly impacted by factors such as wind and gravity. Thus, the design of the rifled barrel and its grooves directly contributes to the performance of the firearm in terms of bullet stability and accuracy during flight.