breech closer

English Thesaurus

1. a metal block in breech-loading firearms that is withdrawn to insert a cartridge and replaced to close the breech before firing (noun.artifact)

hypernym	:	block, blockage, closure, occlusion, stop, stoppage,
definition	:	an obstruction in a pipe or tube (noun.artifact)

part meronym	:	breech, rear of barrel, rear of tube,
definition	:	opening in the rear of the barrel of a gun where bullets can be loaded (noun.artifact)