Semi-Auto and Pump-Action Long Gun Triggers

by
posted on March 28, 2017
longgun.jpg
Nearly all contemporary semi-automatic and pump-action sporting rifles have an underride trigger with an internal hammer cocked by rearward motion of the bolt or bolt carrier. A notch or shelf on the hammer is engaged by the sear to retain it in the cocked condition. Pulling the trigger disengages the sear from the hammer, allowing it to fly forward to hit the firing pin and fire the gun.

Most fire-control assemblies for semi-automatic and pump-action rifles are held in the receiver by pins, screws or levers. The trigger is not readily adjustable. 

Typically, semi-automatic and pump-action shotguns also have an internal hammer cocked by the rearward motion of the bolt or bolt carrier. A non-adjustable underride trigger system pinned inside the receiver retains the hammer in the cocked position by sear engagement on a notch in the hammer. Pulling the trigger disengages the sear from the hammer, allowing it to fly forward to strike the firing pin.

In addition to fire control, the trigger mechanisms for semi-automatic and pump-action shotguns must also perform several functions related to shotshell feeding. When the gun is fired and the bolt and bolt carrier move rearward, the fire-control system pivots the shell carrier downward and depresses teh shell latch on the magazine tube to release the next shell onto the shell carrier. On the bolt's return trip forward, the shell carrier pivots upward, positioning a fresh shell directly in front of the chamber. As the bolt goes into battery, the fresh shell is chambered and the action's locking block or locking lugs engage the receiver or barrel extension.

An important part of the fire-control mechanism of any semi-automatic or pump-action firearm is the disconnector. After a shot has been fired, the shooter's finger may still be on the trigger as the action cycles to cock the hammer or firing pin. The disconnector prevents the cocked hammer or firing pin from falling unless the trigger is first released, then pressed again.

The disconnector can be a separate part, or it may be designed into the trigger bar, sear or other components of the fire-control system.

Latest

Eaa Girsan Mc14 T Lady Tip Up
Eaa Girsan Mc14 T Lady Tip Up

First Impressions: EAA/Girsan MC14T Lady Tip Up Pistol

It's not just a cute name; it's a CCW-ready handgun designed with the modern woman in mind.

Mastering Sight Picture, Sight Radius & Hold

There are three simple things that affect your marksmanship with every shot; two of them are under your control, and the third depends on your firearm.

Hurry! NRA Family's Last-Minute Holiday Gift Round-Up

There's no minute like the last minute, is there? Try one of these down-to-the-deadline delights this season!

NRA Family Events: Meet Silencer Central at RMEF Hunter & Outdoor Christmas Expo

Meet America's leading silencer solution (& 200 other premier outdoor companies) this December 7-16 in Las Vegas!

NRA Family Entertainment: Savage Journeys & Bonding in the Wild

Whether you're the "strong, silent" kind of dad or your son's best buddy, this episode of Savage Journeys is the video to fill your heart.

Video Review: Rossi RM66 Revolver

Chambered in .357 Mag., this jumbo revolver was created for hunters and target shooters alike.

Interests



Get the best of NRA Family delivered to your inbox.