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.

U

UNDERBOLT

The moveable lock of some break-open firearms. It normally engages the barrel lug (underlug) and is actuated by the top lever.


UNDER-LEVER ACTION

The same as a top break mechanism except that the lever that unlocks the firearm, allowing the barrels to pivot and expose the breech, is located below the trigger guard or forms the trigger guard.


UNDERLUGS

The downward projecting lugs at the breech end of a break-open firearm used for locking and barrel positioning in the frame. Also called Lumps.

Also Known As: Lumps


UNIBODY SHELL

1. A shotshell component having the body and basewad as a single unit with a metallic cup. Sometimes called Unibody Shell. 2. A complete round of ammunition having the body and basewad as a single unit without a head of a different material.

Also Known As: One Piece Shotshell


UNIVERSAL RECEIVER

A heavy duty mechanical device into which chambered barrels are secured for testing ammunition.


UNLOAD

1. The complete removal of all ammunition from a firearm and it’s magazine 2. Disassembly of a cartridge or shell.


U-NOTCH SIGHT

A rear sight on pistols or revolvers having a flat top with a “U” shaped notch used with bead-topped front sight. Named after Ira Paine, 19th Century match and exhibition shooter. Also known as Paine Sight.

Also Known As: Paine Sight


UNSERVICEABLE

A firearm which, for any reason, is no longer fit for firing.


UPSET FORGING

A gun barrel blank formed by hammering a steel bar to increase its diameter at one end for the purpose of providing a shank section.