Variable volume chamber cannon

An assembly for effecting a variable volume chamber for use in a cannon having a barrel, the barrel having at least one certain bore diameter defined about a bore axis and having a muzzle end and an opposed breech end, a single chamber disposed at the breech end, and a breech assembly operably coupled to the chamber, the assembly comprising;

• the chamber having a fixed diameter region of a chamber wall, a breech plug assembly selectively axially translatable in the fixed diameter region of a chamber wall and rotatable to effect locking at a desired disposition in the chamber,
• and a breech seal that is axially translatable responsive to the rotational locking of the breech plug assembly to effect a breech seal diameter increase that compressively, sealing engages a seal margin with the chamber wall.

A method for effecting a variable volume chamber for use in an automated cannon having a barrel, the barrel having at least one certain bore diameter and having a muzzle end and an opposed breech end, a single chamber disposed at the breech end, and a breech assembly operably coupled to the chamber, the method comprising;

• defining a fixed diameter region of a chamber wall;
• defining a known volume of the chamber, the known volume for receiving therein a projectile and a volume of propellant by means of by a circumferential inner wall margin and having a known depth dimension and;
• defining a chamber variable volume by disposing a breech plug assembly in the chamber to a selectively variable depth, the depth being less than a known depth of the chamber such that the breech plug assembly fills a first selectively variable portion of the known volume of the chamber, thereby leaving a second variable portion of the known volume of the chamber free and defining a chamber variable volume.

A variable volume chamber assembly for a cannon, comprising:

• a chamber having a fixed diameter region of a chamber wall, a breech plug assembly selectively axially translatable in the fixed diameter region of a chamber wall and rotatable to effect locking at a desired disposition in the chamber,
• and a breech seal that is axially translatable responsive to the rotational locking of the breech plug assembly to effect a breech seal diameter increase that compressively, sealing engages a seal margin with the chamber wall.