What is the purpose of the Swiss groove?

The purpose of the Swiss groove in artillery, particularly in howitzers like the M777A2, is to hold the propellant charges in place. The design of the Swiss groove allows for a secure fit that keeps the propelling charges stable during firing. This stability is essential to ensure that the charges ignite consistently, which directly affects the performance and effectiveness of the artillery piece.

Without the Swiss groove, there would be a risk of charge movement, which could lead to inconsistent firing and affect the overall accuracy and reliability of the howitzer. By securely holding the charges, the Swiss groove ensures that each shot is fired under the same conditions, contributing to the weapon's accuracy and operational effectiveness.