Trigger terms glossary


June 17, 2005, 12:45 AM

Could anyone please help define these trigger descriptions, or add others I missed? I (and maybe other folks) will appreciate a better understanding of these terms. I know a few of these, but please assume I don't know anything at all about triggers.

Also, any advice in "layman's terms" on testing triggers on new guns to find the "pick of the litter", as well as what defines a bad trigger requiring an upgrade would be really helpful.

Thank You Very Much,

0) adjustable trigger
1) backlash
2) break
3) creep
4) crisp
5) engagement
5a) hair trigger
6) heavy
7) length of pull / pull length
8) lock time
9) long
10) over-travel
11) pre-travel
12) pull
12a) reset
13) rough
14) sear break
15) short
16) slack
17) takeup
18) trigger slap
19) trigger stop

If you enjoyed reading about "Trigger terms glossary" here in archive, you'll LOVE our community. Come join today for the full version!
Jammer Six
June 17, 2005, 02:02 AM
0) adjustable trigger: a myth.

1) backlash: the reaction you get from your wife when you buy a trigger job. "Oh, it wasn't just fine the way it WAS?"

2) break: what weapons do when you do your own trigger job.

3) creep: the effect doing your own gunsmithing has on the price of your weapon.

4) crisp: another myth.

5) engagement: the first portion of the sear you eliminate when you do your own trigger work.

5a) hair trigger: the trigger on a full automatic 1911.

6) heavy: a trigger that won't allow the hammer to fall after you do your own trigger work.

7) length of pull / pull length: the amount of distance between the point of aim and the hole your bullet leaves. See number 12.

8) lock time: the amount of time between the time a barrel swells up, (usually by firing a live round behind a squib round) locking the slide to the frame and the time you find a big enough hammer and a vice to pound the slide off the frame.

9) long: see number 15.

10) over-travel: shooting to the right of your target (for a right handed person).

11) pre-travel: jerking to the left before you pull the trigger (for a right handed person).

12) pull: what you do when you mean to squeeze.

12a) reset: the amount of time you have between shots with a full automatic 1911.

13) rough: what your first successful trigger job will be.

14) sear break: see number 2.

15) short: see number 9.

16) slack: the amount of rattle the first trigger you install will have in it's track.

17) takeup: what your girlfriend will do with her gunsmith if you do a trigger job for her.

18) trigger stap: the metal filings that come off the sear when you use a dremel on it. See "doughnut hole".

19) trigger stop: a condition caused by using a dremel on the sear, to shorten the sear hooks to the point where the trigger bow wedges under them and stops the first time it is pulled. (See number 12)

Jammer Six
June 17, 2005, 05:46 AM
I just realized that you used an "a" twice, simply to alphabetize your questions.

Only a programmer would have eschewed capitals, and started from zero, but an Old School programmer (as in Basic, before Visual Basic, or even C) would have numbered them in increments of at least five in the first place.

My suggestion is simply this: if you like the way the trigger feels, it doesn't matter what anyone else thinks, or which words they use attempting to communicate what they think.

Conversely, if you don't like the way the trigger feels, it needs to be upgraded, and then it doesn't matter what anyone else thinks, or which words they use attempting to communicate what they think.

June 17, 2005, 12:19 PM
Pre-travel, slack and take up are the same, use slack....Hair trigger is meaningles , we measure trigger pull in lbs and ozs....Back lash and overtravel are the same and are removed with a trigger stop....Sear break -replace it...Lock time is the time from relase of sear by the trigger to the strike of the firing pin on the primer...

June 17, 2005, 12:32 PM
is pre-travel the slop between the front dohickey and the rearmost thingamajig?
i never should have done that!! just could not resist

June 17, 2005, 12:58 PM
I'll try a non-sarcastic stab at this... the ones I'm not competent to explain I've left blank, and I fully expect some folks will want to pick nits about some of my definitions.

Oh, and Jammer? Your advice about liking what you like is not bad, but it's hardly useful for someone who's trying to get an idea of what the trigger might be like on a gun he's never fired but his friend has.

0) adjustable trigger -- a trigger that is "easily" adjusted by the user to have a different pull weight. (See #s 5 & 6)

1) backlash

2) break -- the point at which the trigger allows the hammer to fall, accompanied by a sudden release of tension. The ideal break is sudden and definite.

3) creep -- a trigger is said to creep when it does not have a consistent, clean break. Once the trigger reaches the break point, it should not be possible to move it further to the rear, even slightly or slowly, without a crisp break.

4) crisp -- sudden and definite, with no extra movement possible.

5) engagement

5a) hair trigger -- a trigger that breaks from an extremely light touch. Trigger pull weight is measured by the number of pounds of pressure required to pull the trigger past the break. A "hair trigger" is a trigger that could be pulled past the break by the weight of a single strand of human hair. Obviously a descriptive term that is never strictly accurate, it is often used in news stories to denote a trigger that can easily be pulled by a normal human being instead of by someone with the hand strength of an upland gorilla.

6) heavy -- a trigger that requires a lot of pressure to be pulled past the break. "Heavy" is subjective and depends upon the gun type, but generally speaking, in a handgun anything under 4 pounds is light, and anything over 6 or 8 pounds is heavy. Rifles usually have much lighter triggers than handguns, and thus "heavy" on a rifle might be "light" on a handgun.

7) length of pull / pull length -- the distance the trigger must travel in order to fire a shot.

8) lock time

9) long -- a trigger with an exceptional length of pull. Like "heavy" and "light," "long" is a subjective term which depends upon the type of gun.

10) over-travel -- after the break, the trigger should stop completely. If it does not, that's over-travel, so called because the trigger keeps "traveling" after its journey is completed.

11) pre-travel -- Some triggers can be pulled slightly backwards before you can feel any tension and before any other movement is initiated within the gun -- thus, this is travel that begins before the trigger is doing any work at all.

12) pull -- see #s 5, 6, & 7. Pull describes the entire sensation of making the trigger complete its journey past the break.

12a) reset -- The point of the trigger's return journey at which the gun's internal mechanisms are ready to fire another round. On many guns, after the shot has fired, if you hold the trigger to the rear and then slowly release it, you can feel or sometimes hear an audible 'click' as the trigger reaches the reset point. (Doing this every time while re-aligning the sights is called "follow through," and it helps to improve accuracy. The next shot is then fired from the reset point, rather than allowing the trigger to complete its return toward the front.) The reset point varies greatly from one type of gun to another, and some guns do not reset until the trigger has been allowed to complete its entire return journey.

13) rough -- a gritty or inconsistent feel to the trigger pull.

14) sear break

15) short -- the opposite of long. A trigger that doesn't have to travel very far before the break.

16) slack -- see #11.

17) takeup -- see #s 11 & 16

18) trigger slap -- flapping your finger onto the trigger and yanking it to the rear, usually accompanied by flapping your finger immediately back off the trigger at the moment the shot fires. A bad thing, because it invariably misaligns the sights and sends your shot wild.

19) trigger stop


With a knowledge of the name comes a distincter recognition and knowledge of the thing. -- Henry David Thoreau

June 17, 2005, 01:17 PM
"A "hair trigger" is a trigger that could be pulled past the break by the weight of a single strand of human hair."

Get a Jewel adjustable target trigger. Set it down to about 2 ounces. Pull hair from head, place in front of trigger. Hold both ends of hair and pull trigger.

Works on mine! :)

June 17, 2005, 01:57 PM
Other terms:

20) reach -- the reach is determined by the measurement from the backstrap to the face of the trigger. The shorter the reach, the smaller the hands that will easily be able to fire the gun.

21) mushy -- similar to creep, it denotes a trigger that has a squishy or uncertain feel, especially around the break point.

22) stacking -- a noticeable increase in pull weight as the trigger travels. Ideally, the trigger pull should be the same weight throughout its entire journey.


June 17, 2005, 10:53 PM
Moved this over to Gen'l, hoping for some good discussion & clarifications.


June 19, 2005, 11:18 AM
Just to fill out Pax's list some:

5) Engagement the relationship between the trigger and the sear, specifically the bearing surfaces of each

8) Lock Time the amount of time between the release of the sear and the round going off.

18) Trigger Slap (definition 2) a condition wherein after firing, the trigger comes back and "slaps" the shooter's trigger finger.

19) Trigger Stop a mechanism for adjusting overtravel (see Pax's #10)

June 25, 2005, 04:23 AM
7) length of pull / pull length

Actually when discussing triggers it should be stated as pull distance

Length of Pull is a general firearms term regarding stock dimensions of a rifle or shotgun.

Pull is the distance from the center of the trigger to the center of the buttplate.
For instance the Length of Pull on an M1 Garand is 13".

rust collector
June 25, 2005, 02:38 PM
The pre-travel term lets us segue into the two-stage trigger, common in military and target firearms, in which there is a section of the trigger pull that is light but uses leverage to move the sear close to the break point. The second stage is shorter and sear release can be more closely controlled. Most sporting firearms sold in the states use a single stage trigger.

Not to be confused with the set trigger, also much more common in Europe, in which a single trigger may be moved forward or one of two triggers is moved back to "set" a system of levers that permits a very light pull.

Isn't triggernometry fun?

June 25, 2005, 09:50 PM
0) adjustable trigger: A trigger in which one or more parameter may be easily adjusted by the user. The most common adjustment is pull weight, but a fully adjustable trigger may be adjustable for pull distance, individual trigger stage distances, individual trigger stage weights, release point, left/right cant, overtravel, and possibly others I'm forgetting.

6) heavy: Subjective--over 5lbs SA or 8lbs DA in a pistol, or over 3lbs in a rifle.

8) lock time: Amount of time between the "break" (sear release) and the projectile exiting the muzzle. I've also seen it described as the time between sear release and primer ignition, but generally the time for the projectile to travel down the barrel is included.

11) pre-travel: Also called first stage.

12a) reset: The point at which during the release of the trigger after a shot is fired one can stop releasing the trigger, begin pulling the trigger again and expect it to function properly.

If you enjoyed reading about "Trigger terms glossary" here in archive, you'll LOVE our community. Come join today for the full version!