Since the late 1950’s, Eugene Stoner’s original M16 design has changed through the years, even though it was at the time radical in appearance and built of “space age” materials. But the trigger group had a problem a sloppy and inconsistent pull running through various models and versions.
After arms manufacturers delivered the AR-15 to the civilian market in a legal, semi-automatic form, the demand for an improved fire control system arose. Responding to the demand, there was soon an avalanche of upgraded triggers.
Comparison of the Best AR Drop in Triggers
Timney AR-15 Drop-in Trigger Module
Fostech Outdoors - AR-15 AR II Echo Drop-In Binary Trigger
James Madison Tactical - AR-15 Saber Drop In Single Stage Trigger
Patriot Ordnance Factory - AR-15 Drop-in Trigger
What is a Drop-in Trigger?
The standard triggers on most factory rifles consist of separate and loose pieces. This makes their installation more difficult. They end up with varying spaces between them
The newer concept of a drop-in trigger is a significant departure from the mil-spec AR-style fire control group. It means that the hammer, trigger, and disconnector are joined in a single case. This allows for an exact relationship between sear and hammer since the hammer and trigger pins in the housing are kept in the same relative locations.
Advantages of Drop-in Triggers
This way, the popular self-contained "drop-in" triggers have solved two issues with stock AR fire control groups (FCGs) and AR trigger upgrades respectively. They’re now easier to install as well as being more consistent. In fact, drop-in triggers don't require any gunsmithing or specialized skills for installation.
Although the popularity of the drop-in trigger has been linked to more recent times, it actually first appeared over 50 years ago. For instance, the famous Russian Dragunov SVD marksman rifle from the early 1960s had a drop-in trigger group. The same is true of the lesser-known Taiwanese T86 assault rifle (an AR-15 clone) from the late 1990s.
Disadvantages of Drop-in Triggers
One disadvantage of drop-in, self-contained modules is the non-adjustable trigger pull weight. This is set at the factory and typically fixed with thread locker because the end user is not supposed to touch it.
However, customers generally do have an option of selecting between 3, 4, and 4.5 lbs at the time of purchasing. It’s just the fine-tuning afterward that is an issue.
Currently, many modular fire control units are available, including both single- and two-stage systems. In these short reviews, we’ll present some of the more popular drop-in AR-15 triggers out there.
Quick Take - Best AR-15 Drop-in Triggers
These are our recommendations for the best drop-in triggers for the AR-15:
Review of the Best Drop-in Triggers for the AR-15
Keep reading below for more in depth reviews of each trigger.
Our Top Pick:
Timney AR-15 Drop-in Trigger Module
The first self-contained "drop-in" trigger comes from the eldest and most reputable gun part manufacturer Timney Triggers, established in 1946. Many of their models are painted gold, appropriately. Timney is the gold standard for aftermarket triggers, and their AR-15 Drop-In Trigger module is no exception.
The most striking thing about this trigger group is that all components come in a shiny yellow aluminum housing. That’s what catches the eye, but the best thing is that it requires no gunsmithing or crazy modifications. Just drop it in with your factory AR hammer and trigger pins or new KNS pins.
As expected from such a reputable manufacturer, this trigger provides smooth, crisp, creep-free pull. It feels more like classic bolt action than a battle rifle trigger. Timney provides a very clean break with a short reset. That means you can quickly shoot a lot of rounds without much motion of your trigger finger.
Though this drop-in has a set screw for adjusting trigger return/pull weight, the Timney is tuned by the factory and then locked down. This single-stage trigger comes with a preset pull weight choice of 3 lb., 4 lb. or 4.5 pounds and features standard solid, slightly curved trigger bow.
The components are machined from tool steel heat-treated to 56-60 Rockwell case hardness for long service life with superior impact resistance. Besides trigger and hammer pins, the drop-in cassette is also secured by the set screws in the floor of the lower receiver.
The innovative CMC triggers were created by competitive shooter Chip McCormick and belong to the more affordable drop-in line of AR-15 triggers on the market. The CMC Tactical Trigger has a light, crisp break with almost nonexistent overtravel. It has a short trigger reset of roughly 2mm. The preset pull measures 3½ lb. pull.
This excellent match-grade single-stage trigger has all internal components tweaked at the factory to minimize take-up and over-travel. It comes in a stainless steel sheet metal trigger housing.
The entire module is held in the receiver by two slightly-oversized center pins to prevent trigger wobble. CMC offers its Tactical trigger group with a traditional curved trigger shoe or a skeletonized flat shoe.
If you’re really itching to have one of the best triggers you can possibly put on your AR-15, then check out the Fostech Outdoors AR-15 AR II Echo Drop-In Binary Trigger. Not for the light of heart, Fostech Outdoors manages to make triggers that are more exciting than a trigger probably should be. One of the fastest, crispest triggers on the market, you’ll get a solid sports trigger in this offering.
This ATF-approved trigger aims to squeeze every little bit of response time and delay between shots possible out of your AR, making it an excellent choice for having fun at the range. The trigger itself offers three separate settings. You have a safe mode, which obviously will not allow the firearm to fire. The semi-automatic mode fires when the trigger is pulled. And lastly, echo mode fires when the trigger is pulled and also when the trigger is released.
However, Fostech Outdoors also makes safety a priority. If in echo mode, depressing the trigger provides a built-in safety to prevent the second round from firing—simply moving the selector to the safe position. This is fast, easy, and efficient. Not only is it a great safety feature, but it also can reflexively be used to prevent the second round from firing to avoid wasting ammunition on a moving target.
If you’ve been following AR-15 accessories for a while, it’s worth mentioning a notable change. This trigger, at first launch, came with a stripped carrier with a gas key. After listening to customer feedback, Fostech Outdoors changed this, as customers didn’t like dealing with a proprietary carrier. The current-generation Echo AR-II does not need a proprietary carrier. We mention this not only to inform our astute readers, but to highlight the kind of customer service and quick reaction time Fostech Outdoors has.
Overall, these innovative features cater more to sport shooting than practical use, but we strongly recommend anyone with an adequate budget try this trigger out. Who knows, you might love it enough to take its performance features into the field.
If you didn’t know a trigger could be a lot of fun, you owe it to yourself to try out the Fostech Outdoors AR-15 II Echo Drop-In Binary Trigger, an exercise in how innovative something as simple as a trigger can be. While it’s a niche, premium trigger, we think it’s worth trying out for the fun factor alone.
If you’re looking for a great replacement to your stock trigger that’s well-rounded in functionally, the James Madison Tactical AR-15 Saber Drop-In Single Stage Trigger is a good choice. Compatible with both the AR-15 as well as the AR-308, it offers versatility for gun owners who prefer to keep their stock standard.
We like that it has a very fast reset for a faster response time between shots. While it’s obviously not going to do any wonders, you can certainly feel the difference compared to other single stage triggers, let alone the stock trigger. This also helps improve response time, especially combined with the crisp release.
The trigger is nicely curved, making it very ergonomic and natural-fitting. Made from 17-4 stainless steel throughout its primary construction, from the hammer and trigger, to the disconnect, it will last a long time. The parts all feel solid but fluid, as they should. Chalk that up to the casing unit, which is made from high-grade, 6061-T6 aluminum and 17-4 ph SS, which while about on par with stainless steel in terms of durability, offers a lowered friction, making it all slides smooth as butter.
While any drop-in trigger, by definition, is going to be much easier to install than more complicated components, the design of this trigger is very intuitive during installation. Each part seems to stand out very well and not be designed in a way that would obscure anything. While installation of a drop-in trigger is fairly simple, it would be a great first upgrade for this reason.
Overall, there’s a lot to love with this trigger. It’s premium quality, smooth as silk, and both looks nice and is easy to install thanks to its fluid design. The only downside might be that there isn’t anything particularly unique here. Still, if you want a solid trigger at a great price point, check out the James Madison Tactical AR-15 Saber Drop-In.
This is a premium quality trigger with solid parts that will stand up to lots of use. You will love the quick reset and crisp, smooth operations. There is nothing super unique or different about this trigger, but it is a perfect option that is easy to install for even first-timers.
Another favorite drop-in trigger group comes from Patriot Ordnance Factory (POF), a US firearms manufacturer based in Phoenix, Arizona. They produce a line of impressive AR-15 triggers for competition, hunting, and tactical applications.
Since 2004, POF has provided AR enthusiasts with several varieties of the self-contained drop-in triggers as well as an Enhanced Finger Placement trigger. All components are machined from A2 tool steel. They are nitride heat-treated to 70 Rockwell case hardness for the best strength and corrosion resistance.
This simple hard-coat anodized aluminum cassette comes with rubber urethane bumpers on the bottom instead of Timney set screws. An anti-rotate stainless steel pin kit made by renowned KNS Precision is included in the package, too.
The improved POF EFP (Enhanced Finger Placement) trigger supports the tip of your finger at the same low resting site for a precise and consistent trigger pull every time.
The custom-designed single-stage, non-adjustable POF EFP features a semi-curved trigger shoe with a solid 4.5-pound pull weight.
Canadian company TriggerTech differs from traditional functionality by using a roller bearing system, as opposed to their competitors who utilize designs with pivots and polishing to try to attain the best break possible.
TriggerTech uses rolling friction in the form of Frictionless Release Technology (FRT). Their designs, based on the roller system, help contribute to the minimal wear and tear on engagement surfaces. This helps ensure durability and high-end performance.
TriggerTech produces a non-adjustable drop-in triggers with a 3.5 or 5.5-pound pull depending on the model. The adjustable version can be adjusted from 2.5 to 5 pounds. You can make those adjustments with the supplied Allen key. Every turn of the trigger adjustment screw has an audible click that measures approximately 2 ounces.
TT-AR-15 two-stage triggers give you a clean break and have a minimal trigger reset of roughly 1mm without the worry of accidental discharge.
The TriggerTech TT-AR-15 comes in a housing made of aluminum. The rest of the working components are constructed with hardened corrosion-resistant stainless steel.
This Canada-based company started as a crossbow trigger manufacturer. Today they offer a variety of AR-15 drop-in triggers available in curved or straight blade trigger variants.
Once again our journey to the best drop in triggers brings us to Phoenix, Arizona. This time we visit a newer company called Velocity Triggers. Velocity was founded in 2008 by Tom Vehr, a designer and engineer with over 30 years of experience in manufacturing and assembling triggers for well-known makers such as Timney Triggers and Knight Rifles. The experience he brought from his former company is most easily seen in the personal feel similar to the Timney. But Velocity installs a little easier and costs less.
Velocity says their trigger-pull quality rivals a nice bolt-action rifle. A decent cost is another selling point - it’s about half the price of a lot of other aftermarket AR-platform triggers.
Velocity Triggers offers a true drop-in replacement trigger for standard AR-15 style weapons. Installation takes less than five minutes and requires triggers pins that are sold separately.
All Velocity Triggers are single-stage. They have a short and positive reset that is suitable for precision shooting as well as for 3-gun style competition use.
Despite its low cost, Velocity Triggers do not sacrifice quality. Their components are cut from tool steel with a very precise Wire EDM process. This is more accurate than almost any CNC mill.
The parts are heat-treated for the necessary hardness. The trigger housings are machined from 6061 T6 billet aluminum and coated with a green anodizing. Seven models are currently offered with trigger pulls ranging at 3, 4, and 4.5 lbs. All are available with curved or straight trigger blades.
As a novelty, they’ve recently introduced two new models to work specifically with the often-problematic steel-cased ammunition and 22LR conversions. Both models are available with either a straight blade or a curved blade. They have a 4.0-pound pull weight.
How to Replace an AR-15 Drop-in Trigger
If you’ve ever wanted to replace your AR-15 trigger for crisper operation and improved performance, a drop-in trigger certainly makes the process easier. However, you’ll still want a guide, so read on. This relatively simple installation can be done quickly and easily if you read our guide and reference the included video to help you follow along.
- As always, make sure your weapon is unloaded.
- Remove the magazine.
- Remove the upper and lower receiver, and set them aside.
- De-cock the hammer, but do not let it strike the front of the receiver when doing so.
- Punch out the hammer and trigger bins using a punch and light hammer. You’re not trying to get the trigger removed, just the hammer.
- There will be a grip screw inside the grip to let the handle (or the grip) to drop about half an inch or less. Loosen this screw, but be careful not to lose the spring that’s located on the upper-right, top edge of the grip, as well as the detent pin on the right wall of the receiver.
- Remove the safety from the receiver. The trigger should now be loose, so remove that as well.
- After you remove the AR trigger and the hammer, lower the trigger assembly into the receiver.
- Insert the pins that come with the trigger kit, securing them on the far side of the receiver. You should have some C-clips for this step that also come with your trigger kit.
- Now you can reset the safety, but make sure that the lever is oriented properly.
- Insert the safety spring and detent pin.
- Reinstall your grip and tighten the grip screw.
- That’s it! You now have a new drop-in trigger that should make your AR-15 much more fun to shoot.
An AR-platform rifle is an ideal "kit" gun for do-it-yourselfers. A drop-In trigger is a logical upgrade for any AR fanatic to help you build a system tailored to your needs and preferences.
A simple drop-in installation matched with quality and precision-built trigger components will give you uniformly good, clean, crisp trigger pulls. In turn, this will lead to a consistent, tight shot group.
Aftermarket drop-in triggers can be pricey, but there are many affordable and quality self-contained triggers from a number of different manufacturers. Don’t feel trapped with the standard, gritty stock trigger of AR-15!