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// Parts · Triggers · Guide
The AR Trigger, Explained
What the parts do, why one trigger fits so many rifles, and how to choose between single- and two-stage, curved and straight, light and heavy. Written by the people who fit them — and honest about where our own range stops.
// 01 · What it does
Five parts and two pins decide how every shot breaks.
The AR fire-control group is small and simple. Its job is to hold the hammer back, let it go when you decide, then catch it again while the rifle cycles so it can’t follow the bolt home.
Trigger and sear
The trigger carries the sear that holds the hammer. How that sear is cut and finished sets the feel: the take-up, the wall, the break.
Hammer and spring
The hammer strikes the firing pin. Its spring has to deliver enough energy to fire hard military primers every time — which is why we never cut it.
Disconnector
As the carrier drives the hammer back, the disconnector catches it. When you ease off the trigger, it hands the hammer back to the sear. That hand-off is the reset.
One shot, start to finish
- Cocked. The sear holds the hammer under spring tension.
- Break. You press the trigger; the sear releases the hammer and it strikes the firing pin.
- Catch. The carrier pushes the hammer back down while you’re still holding the trigger, and the disconnector catches it.
- Reset. You ease the trigger forward; the disconnector releases the hammer to the sear with a click you can feel. The rifle is ready for the next press.
// 02 · One footprint
Why one trigger fits so many rifles.
The AR-15 lower has a standard trigger pocket with two cross pins, each 0.154″ in diameter. Most AR-10 and SR-25 pattern lowers copied it, and a long list of rifles and pistols from other makers was built around it. That shared footprint is why the triggers on our page are listed for AR-15 and AR-10, rifle and pistol. The one exception is the AR-9 and other pistol-caliber builds — see below.
Where the footprint stops
- Large-pin lowers. Some older and proprietary receivers use 0.170″ pins. A small-pin trigger needs adapter pins there, or a different trigger.
- Proprietary large-frame lowers. A few AR-10 designs changed the pocket. Tell us the make and we’ll check before we fit anything.
- Tight billet pockets. Some billet lowers are machined close; a trigger that fits a forged lower may need checking in one.
- AR-9 and other pistol-caliber builds. A pistol-caliber lower may share the pocket, but most run on straight blowback, which hits the hammer and disconnector harder. A trigger that fits is not the same as a trigger that is approved.
Not approved for AR-9. None of the triggers we sell — the LaRue MBT-2S or the Geissele G2S®, SSA® and SSA-E® — is approved for AR-9 or other pistol-caliber AR builds, or for the SIG MPX/MCX. Our lowers are rollmarked CAL: MULTI, which invites a pistol-caliber upper; if one is on the plan, tell us before we fit a trigger.
// 03 · Single or two-stage
Two ways to break a shot.
Single-stage
One continuous press: a little take-up, then the break, with no wall in between. Simple and quick to learn, and the classic mil-spec trigger is single-stage. The cost is that the break can arrive before you expect it, or the creep before it can feel gritty.
Two-stage
A light first stage of take-up stops at a distinct wall. A short, light second stage then breaks the shot. You take up the slack with the decision still unmade, and the shot goes when you add the last few ounces — not before.
Every trigger we fit is two-stage. Most of the weight sits in the first stage, so the trigger is deliberate to start and light to finish. On the designs we fit, the trigger resets to the wall, so a follow-up shot needs only the second stage.
The words you’ll see on a spec sheet
| Term | What it means |
|---|---|
| Take-up | Movement before the trigger meets resistance. On a two-stage, this is the first stage. |
| Wall | The point where the second stage begins. Crisp is good; mushy is not. |
| Creep | Movement you can feel after the wall and before the break. Less is better. |
| Break | The moment the sear lets the hammer go. |
| Overtravel | How far the trigger keeps moving after the break. |
| Reset | How far the trigger must come forward before it will fire again. |
| Pull weight | The force to fire, measured in pounds. Makers publish ranges, not single numbers — a trigger at the top of its range is in specification. |
// 04 · Pull weight
Match the weight to the rifle’s job.
The right weight is the one that suits how the rifle will be used, and under what stress. Here is how we fit our own range against the jobs our customers bring us.
| The rifle’s job | What matters | Where we start |
|---|---|---|
| Duty, patrol or agency | A heavier, deliberate press and a record behind the part | Geissele SSA® — Crane safety certified, laser marked and lot traceable. Or the LaRue MBT-2S on its 6.0 lb spring. |
| General-purpose carbine | A clean, predictable break at a sensible weight | LaRue MBT-2S on its 4.5 lb spring — our standard fit — or the Geissele G2S®. |
| Home defense | Control under stress, not the lightest break | LaRue MBT-2S or Geissele G2S®. |
| Precision, DMR or SPR | The lightest, cleanest second stage | Geissele SSA-E® — 0.9–1.3 lb second stage, the lightest break we fit. |
// 05 · Curved or straight
Bow shape is a preference, not a price tier.
Curved bow
The traditional M4 profile. The curve places the finger in the same spot every time and feels familiar to anyone who learned on a military rifle. All three Geissele triggers we carry are curved.
Straight (flat) bow
A flat face gives a single repeatable contact point lower on the blade. The extra leverage makes the same spring feel slightly lighter at the fingertip. The LaRue MBT-2S Straight Bow is the same trigger and the same price as the curved.
// 06 · Cassette or components
How the parts go in.
Drop-in cassette
The hammer, trigger, disconnector and springs come pre-assembled in a housing that drops into the pocket and is held by the pins. Quick to install, and the engagement is set at the factory.
Individual components
The parts are installed one by one, the way a mil-spec trigger goes in. The LaRue and Geissele triggers we fit are built this way, and we fit and function check them in the rifle.
// 07 · Fitting and checking
A trigger isn’t fitted until it has been checked.
Every trigger we install goes in exactly as its maker built it — no stoning, no polishing, no cut springs — and is function checked in the rifle before it leaves our facility. If you fit your own, follow the maker’s instructions and run the same check with the rifle unloaded and the chamber verified empty:
- Safe. Cock the hammer, set the selector to SAFE and press the trigger firmly. The hammer must not fall.
- Fire. Set the selector to FIRE and press the trigger. The hammer must fall. Hold the trigger to the rear.
- Disconnector. Still holding the trigger, cycle the charging handle fully. The hammer must stay cocked.
- Reset. Ease the trigger forward until you feel and hear the reset. Press again — the hammer must fall.
If any step fails, the rifle is not safe to fire. Stop and have it checked by a qualified gunsmith — or send it to us.
// 08 · Our five triggers
Two makers. Five triggers. One standard.
| Trigger | Bow | Total pull | Second stage | Price |
|---|---|---|---|---|
| LaRue MBT-2S | Curved | 4.5 or 6.0 lb (two springs) | 2.0 lb | $134.99 |
| LaRue MBT-2S Straight Bow | Straight | 4.5 or 6.0 lb (two springs) | 2.0 lb | $134.99 |
| Geissele G2S® | Curved | 4.25–4.75 lb | 1.5–1.75 lb | $175.00 |
| Geissele SSA® | Curved | 4.25–4.75 lb | 1.5–1.75 lb | $250.00 |
| Geissele SSA-E® | Curved | 2.9–3.8 lb | 0.9–1.3 lb | $250.00 |
Don’t take only our word for it
Pew Pew Tactical’s hands-on review of the best AR-15 triggers for 2026 tested sixteen of them. It named the LaRue MBT-2S its Best Duty Trigger and the Geissele SSA-E® its Editor’s Pick. Read the full review on Pew Pew Tactical. Their figures come from their own gauge; the weights on our pages are the makers’ published ranges.
// Questions
What customers ask us.
Will an AR-15 trigger fit my AR-10?
Usually, yes. Most AR-10 and SR-25 pattern lowers share the AR-15’s trigger pocket and 0.154″ pins, and all five triggers we sell are made for both. A few large-frame lowers use proprietary pockets or larger pins, so tell us the make of the lower and we’ll confirm before we fit one.
Will it fit an AR pistol?
Yes. An AR-15 or AR-10 pistol uses the same lower receiver and the same fire-control pocket as the rifle. Overall length and barrel length change the legal category, not the trigger.
Can I use these triggers in an AR-9?
No. None of the five triggers we sell — LaRue or Geissele — is approved for the AR-9 or other pistol-caliber AR builds, and the Geissele triggers are also excluded from the SIG MPX/MCX. Most pistol-caliber builds run on straight blowback, which hits the hammer and disconnector harder than a gas-operated AR. Our lowers are rollmarked CAL: MULTI, so if a pistol-caliber upper is on the plan, tell us before we fit a trigger.
Is a lighter trigger always better?
No. Weight should follow the rifle’s job. A precision rifle earns a light break; a duty or home-defense rifle is better served by a heavier, more deliberate one. The lightest trigger we fit is the Geissele SSA-E®, and it is built for a marksman’s rifle, not for every rifle.
Can you lighten the trigger I already have?
No. We don’t stone, polish, cut springs or rework sear surfaces. It voids the maker’s warranty, and a trigger that has been changed no longer matches the markings and the specification it was sold under. If you want a lighter break, we’ll fit a lighter trigger.
Why don’t you sell single-stage or drop-in cassette triggers?
Because we fit the triggers we build our own rifles around, and those are two-stage designs installed as individual parts. That isn’t a verdict on every other trigger — it is the standard we can stand behind on a rifle with our name on it.