This invention relates generally to accessories for firearms and more particularly concerns locks for plugging gun barrels.
The use of a lockable plug as a deterrent to unauthorized use or inadvertent or accidental discharge of a gun is well known. Such plugs typically rely on some form of inside-of-the-barrel plug expansion or outside-of-the-barrel plug compression to secure the plug in the barrel.
Plugs which radially expand within the barrel typically rely on frictional engagement against the circumferential wall of the barrel to resist removal of the plug from the barrel. They require complex expanding mechanisms in order to achieve sufficient frictional contact between the barrel and plug surfaces and, while the plug is in the barrel, a substantial portion of their operating structure is usually exposed to tampering outside of the barrel. While they are difficult for the user to install and remove, they offer only modest resistance to unauthorized removal of the plug from the barrel. Since, by definition, their expanding components must exert significant force against the barrel wall, they may all too easily mar or more severely damage the barrel surface in normal use. Because of the complexity of the expanding mechanisms, they generally can be used only with the specific caliber of weapon or length of barrel for which they are designed. In order to provide a more secure locking engagement than is possible with friction type expansion plugs, one variation of the expanding plug approach relies on radial expansion of locking pins. The plug is inserted through a narrow diameter portion of the barrel and the pins then extend into a wider diameter annular groove in the barrel. This grooving is, however, an unacceptable compromise of the barrel wall.
Plugs which operate by radial compression are generally inversions of the expanding plugs above described. They generally combine an in-the-barrel plug with an outside-the-barrel mechanism to secure the plug in place. The plug does not expand against the inner wall of the barrel. It only blocks the passage. It is held in place by an external structure. Some external structures frictionally grip the outer surface of the barrel. Others engage against a protrusion from the barrel to prevent removal. By reason of their compressive forces they, like the expansion plugs, are likely to mar or more severely damage the barrel, though at least only on the outside wall. However, these devices expose most, if not all, of the locking mechanism to outside-of-the-barrel tampering.
It is, therefore, an object of this invention to provide a gun barrel lock which deters unauthorized use and accidental or inadvertent discharge of a gun. Another object of this invention is to provide a gun barrel lock which is easily installed and removed by an authorized user. A further object of this invention is to provide a gun barrel lock which is substantially contained within the barrel. Yet another object of this invention is to provide a gun barrel lock which has most of its structure shielded from exposure to outside-the-barrel tampering. It is also an object of this invention to provide a gun barrel lock which does not exert radial forces against the inside wall of the barrel. Still another object of this invention is to provide a gun barrel lock which can be adjusted to accommodate barrels of different caliber. An additional object of this invention is to provide a gun barrel lock which can be adjusted to accommodate barrels of different length.