The breech block is the principal part of the breech mechanism.

The following terms are used in the component and operation of breech mechanisms:

The breech mechanisms which you've described to us will present much graver difficulties, however.

The breech mechanism has a primer magazine holding 18 primers.

The barrel is a forging screwed into the breech mechanism.

The Model 1871 included a locking bolt in the breech mechanism.

There had been something wrong with the breech mechanism.

The breech mechanism is manually operated in all the guns.

The breech mechanism is similar to that used on the 8 inch howitzers both in design and operation".

It had a heavy, simple breech mechanism with a hydro-pneumatic recoil system.