Letter: J

A malfunction of a firearm that prevents the action from operating; may be caused by faulty parts, ammunition, improper maintenance or improper use of the firearm.

A system of rating the hardness of wood by use of a 0.444 inch diameter ball; measured in pounds required to force one half the diameter of the ball into the wood.

A precise mechanical locating device used in production of component parts and/or assembly of firearms.

A place where two or more parts come together so as to permit motion. The term is sometimes used in reference to the pivot point of a hinged action.

A type of shotgun barrel choke, wherein a slight recess is formed in the bore approximately one inch behind the muzzle. The recess causes the shot to gather before leaving the muzzle resulting in a denser pattern.

The upward and rearward recoiling movement of a firearm when it is fired. See Bullet Jump. See Recoil.