Glossary

The Glossary of Industry terms has been compiled by SAAMI’s Technical Committee to facilitate technical interchanges between members of that committee. It is not intended to provide legal definitions of the terms included, and, in light of further experience, the definitions of these terms may change. It is not intended to be comprehensive since it does not cover the full range of the diversity of the sporting arms and ammunition industry’s products. It is, in other words, a working draft that, it is hoped, may be useful in addressing certain technical matters frequently considered by the Technical Committee and is subject to further change and refinement.

It was the committee’s decision that ONLY industry terms would be included which are unique to the firearms and ammunition industry directly. Optical terms have been omitted for the most part. Common metallurgical terms were not included because they are not unique to the industry. Where there is a common term with a usage unique to our industry, it has, however, been included.

J

JAM

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.


JANKA HARDNESS, JANKA TEST

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.


JIG

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


JOINT

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.

Also Known As: Hinge


JUG CHOKE

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.

Also Known As: Jug Choke, Tula Choke


JUMP

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