breech

breech
/bri:tʃ; britʃ/ n
back part of a gun barrel where the bullet or shell is placed 枪炮的後膛（装子弹或炮弹的地方）
    a breech-loading gun 由後膛装弹的枪炮. Cf 参看 muzzle 2.

牛津英汉双解词典