The distance required for one complete turn of rifling usually expressed as a ratio, e.g., 1 in 10 inches.
Archives: Glossary
Glossary custom post type
TWO PIECE STOCK
A stock consisting of two separate parts, the buttstock and forearm.
TWO-PIECE MOUNT
A telescope mount having two separate base band ring assemblies.
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.
TOP-BREAK ACTION
An action in which the barrel or barrels are connected to the frame by a pivot point. Upon release of the locking mechanism, usually by a top, side or under-lever, the barrel or barrels rotate around the pivot point away from the standing breech.
TRAJECTORY
The curved path of a projectile from muzzle to target.
TRAJECTORY TABLE
A computed table describing the downrange trajectory of a projectile or of shotshell pellets, buckshot or rifled slugs.
TRAP
A clay target throwing device.