Semi-Auto and Pump-Action Long Gun Triggers

by
posted on March 19, 2019
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

man draws from concealment under winter jacket
man draws from concealment under winter jacket

How-To: Winter Concealed-Carry

It may be easier to conceal this time of year, but can you realistically unholster?

Ohio Teen Is CMP's 1st Distinguished Air Rifle Badge Holder

“When I heard about it, I knew I wanted to earn that badge,” Demerle said.

Doctor's Rx To Fix Your Gun Stock's Fit

Is your long gun bringing you up short? Here's what to do.

8 Survival Secrets of America's "Mountain Men"

Some survival secrets should never be forgotten.

Giving Guns As Gifts: Don't Forget the "Batteries"

Gifting a gun this year? Don't forget these critical safety and security accessories!

Reviewed: North American Arms' Ranger II Revolver

It's itty-bitty and teeny-weeny enough for that famous polka-dot bikini...or your robe.

Interests



Get the best of NRA Family delivered to your inbox.