中文翻译与英英解释

枪闩，炮闩；(枪机柄的)螺体。

a metal block in breech-loading firearms that is withdrawn to insert a cartridge and replaced to close the breech before firing
同义词：breech closer,

A breechblock (or "breech block") is the part of the firearm action that closes the breech of a weapon (whether small arms or artillery) at the moment of firing.