Mortar

Claim 2

In a mortar, the combination which comprises: a barrel; a barrel sleeve concentrically attached to said barrel forming exhaust ducts between said sleeve and said barrel, said exhaust ducts extending substantially the entire length of the barrel; an end cap assembly attached to said barrel sleeve and closing one end therefore; a series of drainage and cooling holes in the end cap assembly providing a flow path for cooling air through the exhaust ducts as well as drainage for water trapped by the barrel sleeve; and a variable vent disposed between said barrel and said end cap assembly and adjustable between a closed position and an open position, said vent providing fluid communication from the barrel bore to the exhaust ducts and drainage and cooling holes only when in the open position.

Claim 3

The combination of claim 1 and further comprising sealing means cooperating with the drain and cooling holes to temporarily seal them upon the firing of a cartridge thereby causing the exhaust gases flowing through the variable vent to exhaust to the atmosphere through the ducts formed by the barrel and barrel sleeve.

Claim 4

The combination according to claim 2 wherein the sealing means comprises: an annular plate located over the drain and cooling holes; and a washer spring adapted to hold said annular plate away from its seats.

Claim 5

The combination of claim 1 in which the exhaust ducts formed by the barrel and barrel sleeve form a ring pattern in the annular space between said barrel and said barrel sleeve.

Claim 6

The combination according ro claim 1 and further comprising: at least one range matrix plate attached to the exterior surface of the barrel sleeve; and indicating means cooperating with the range matrix plate such that the range for which the mortar is set may be read directly upon the range matrix plate.

Claim 7

The combination according to claim 5 in which the indicating means comprises a range pointer positioned to indicate range in accordance with the position of the variable vent.

Claim 8

The combination in accordance with claim 1 and further comprising: adjusting means operating upon the variable vent to control chamber pressure and thereby mortar range by opening or closing the variable vent; and indicator means to indicate the range setting of the variable vent.

Claim 9

In a mortar, the combination which comprises: a barrel; a barrel sleeve concentrically attached to said barrel forming exhaust ducts between said sleeve and said barrel; an end cap assembly attached to said barrel sleeve and closing one end thereof; a variable vent disposed between said barrel and said end cap assembly and adjustable between a closed position and an open position providing fluid communication between the barrel bore and said exhaust ducts; a series of drain and cooling holes in the end cap assembly whereby adjustment of the variable vent to an open position provides a flow path for exhaust gases, trapped water and cooling air between the barrel bore and the atmosphere; and sealing means cooperating with The drain and cooling holes to temporarily seal them upon the firing of a cartridge thereby causing the exhaust gases flowing through the variable vent to exhaust to the atmosphere through the ducts formed by the barrel and barrel sleeve, the sealing means comprising an annular plate located over the drain and cooling holes and a washer spring adapted to hold said annular plate away from its seats.

Claim 10

In a mortar, the combination which comprises: a barrel; a barrel sleeve concentrically attached to said barrel forming exhaust ducts between said sleeve and said barrel; an end cap assembly attached to said barrel sleeve and closing one end thereof; a variable vent disposed between said barrel and said end cap assembly and adjustable between a closed position and an open position providing fluid communication between the barrel bore and said exhaust ducts; a series of drain and cooling holes in the end cap assembly whereby adjustment of the variable vent to an open position provides a flow path for exhaust gases, trapped water and cooling air between the barrel bore and the atmosphere; and sealing means cooperating with The drain and cooling holes to temporarily seal them upon the firing of a cartridge thereby causing the exhaust gases flowing through the variable vent to exhaust to the atmosphere through the ducts formed by the barrel and barrel sleeve, the sealing means comprising an annular plate located over the drain and cooling holes and a washer spring adapted to hold said annular plate away from its seats.